Update, September 12, 2012: A new product in this line is now available. Read our review of the iPhone 5 here.
Editors' note: On October 24, 2011, we updated this review after performance testing on an AT&T iPhone 4S. On November 10, 2011, Apple delivered iOS 5.0.1, which promised to fix the battery life issues affecting some users. The update also fixed a security flaw that allowed third-party applications to add unapproved features.
For the first time since the iPhone was born four years ago, a new model didn't arrive in June this year. The wait set the iPhone 5 rumor mill frothing to overflow, so when the iPhone 4S arrived as an incremental upgrade, fanboys commenced an Internet-wide rending of garments. Some critics grumbled that they didn't get more, and I sympathize...kind of. Yes, the lack of 4G is disappointing. And yes, a totally new design would have been fun. But this is hardly the first time that Apple has chosen to make a subtle upgrade. Remember the iPhone 3GS?
The truth is that the 4S brings healthy improvements to an already excellent device. iPhone owners finally get a 64GB model and a better camera, the dual-core processor delivers more speed, and Siri, the iPhone 4S' personal assistant/robot friend/gofer, adds a new and sassy experience. iOS 5 also trots out changes big and small, and we're glad to see Sprint join the Apple family with a true world phone. So while the iPhone 4S isn't the Jesus phone, it's quite enough for plenty of other people-- more than a million, actually.
Not everything impressed me. I'd prefer a slightly larger screen and my list of iPhones misses remains hefty. Call quality and data speeds were better than on AT&T's iPhone 3GS and iPhone 4, but the carrier's network still struggles to compete with Sprint and Verizon. Remember that there will be a discernible difference between the 4S versions (just like we found with the AT&T and Verizon iPhone 4S) so it's important to choose your carrier wisely.
In the end, the decision to buy an iPhone 4S will depend on your current carrier contract. If you aren't eligible for an upgrade with a rebate, I don't think the new features are worth paying full price (at least $500). But if you can upgrade with a discount, or if you're a Sprint customer waiting to get your hands on the iPhone for the very first time, there is enough here to warrant a switch. Sure, there's the chance that a better "iPhone 5" will come next June, but that's a long time to wait. Besides, in the cell phone world, something better is always around the corner.
As I said, the iPhone 4S is indistinguishable from its predecessor. For the most part, that's fine with me. Having lived through the thin phone craze started by the Motorola Razr, I'm not aching for a slimmer device. Granted, the 4S can feel bulky at times, but I continue to enjoy its solid feel in the hand (something that's not always there with skinny phones). I don't have any problems with the handset's general aesthetics, either. A thinner phone may be prettier, but it's what's inside that really counts.
I also can live without some of the rumored "iPhone 5" features, like a wider Home button and a curved profile. The Home button has never plagued me, after all, and I'd prefer to rest the phone flat on a table and tap away. The glass back continues to concern me a bit, particularly after seeing a handful of iPhone 4s fall to their doom. That shouldn't be an issue if you have a case, of course. But speaking of which, some iPhone 4 cases will not fit on the iPhone 4S because Apple moved the ambient light sensor. So if you're looking to dress your 4S, make sure the case fits perfectly before buying. And if you need suggestions, Executive Editor David Carnoy has a few.
My real design gripe is that the iPhone's display is beginning to look rather small when compared with some of the Android competition. Keep in mind that the iPhone's screen has remained at 3.5 inches since the first edition appeared in 2007. At that time, it was plenty big, but as smartphone screens have crept above the 4-inch mark, I now consider 3.5 inches the bare minimum size for a high-end device.
Absolutely, the Retina Display remains stunningly beautiful (as do many Super AMOLED screens), but its size isn't always practical for in-car and hands-free use. Even worse, it can get rather tiring watching a full-length film with the iPhone perched on your airline seat tray table. How much bigger would I want? Nothing too big--the 4.5-inch displays on some Android models are a bit ridiculous--but something in the range of 3.75 inches or 4 inches would be a Goldilocks just right. I'll leave that up to the next iteration of the phone.
At the iPhone 4S' unveiling, one of the biggest elephants in the room was whether the company would mention any differences to the antenna following the iPhone 4's "antennagate." Yet, when Apple VP of Marketing Philip Schiller took the stage, he revealed that the iPhone 4S has two antennas that it can choose between to find the best signal (more on that later). Even if you can't see any changes on the outside, it appears to fix what I found to be a very real problem.
The 4S inherits all the standard iPhone features from the preceding models, including the calendar, voice memos, weather and stock apps, the various clock features, Google Maps, the compass, text messaging and e-mail, and the Notes app. The iPod player is there as well; the 4S splits your music and video libraries into two separate icons. In another change, the 4S also offers an upgrade to Bluetooth 4.0. Though still a growing technology, Bluetooth 4.0 uses less power and will enable the iPhone to talk to small battery-operated devices like Nike+ sensors and fitness machines at the gym. For more on Bluetooth 4.0, check out this deeper dive from Nicole Lee.
The feature that Apple is touting most is the new voice assistant called Siri. It doesn't completely replace the current Voice Control feature--that's still there if you want it--but it certainly does a whole lot more. Basically, Siri both follows commands and answers your requests for information. For example, you can check the weather, ask for a contact's address, set up a reminder, get directions, and ask for obscure trivia. You speak to a robotic female voice (you can't change her identity) and access the feature by holding down the Home button (just as you do to access Voice Control). It uses both your location and a Google search to find a response, so you will need to have a Wi-Fi or cellular connection. The feature is in beta mode and supports English, French, and German. More languages will come later.
On my very first pass the day the 4S was announced, I asked for the next day's weather, the mileage between Cupertino, Calif., and Seattle, a reminder to book air tickets to Chicago, and the capital of Canada. It responded to most of my questions and commands quickly, but it flaked on finding that Ottawa is the capital of our neighbors to the north (according to Siri, she "didn't have enough information"). I'm not sure why that was a problem for her; Siri uses Wolfram Alpha to check facts, which has information on the Canadian city.
On my next pass I tried asking the time in Hong Kong, the current date, where I could get the best burrito by the CNET office, and if Brian Tong is the coolest person ever. It answered the first two questions without any problems, but poor Siri didn't understand our question about Brian. And this time, she did identify Ottawa correctly.
I meant the question about Brian as a joke, of course, but Siri is quite adept at answering a range of queries. When I asked about the best local burrito, she used GPS to give me a list of nearby taquerias with rankings. Yet, not all questions for a preference turned up a good answer. Asking for the best camera, for example, just gave me a list of camera stores. I'm not being critical, since the information Siri delivered was useful--except for listing a Japanese restaurant as a burrito joint--but it is worth noting. On the other hand, Siri didn't hesitate to tell me the best cell phone on the market. "The one you are holding," she replied. Yeah, she can be a bit sassy. I've explored Siri further in this post.
By all means, Siri is a fun and useful feature. Like with FaceTime on the 4S, I got a big kick out of it around the office and I imagine that lots of other people will, too. Over time, I wonder just how much I'd use it, but features like this can surprise you. I asked the same question about FaceTime and I ended up using that pretty frequently while traveling. The challenge for Apple will be to fully integrate hands-free technology. You will be able to activate Siri with a Bluetooth headset (no word on if you can do it with a wired headset), but I understand that car integration is "coming." Given the abundance of hands-free driving laws, it's important that Siri is fully accessible to drivers while they keep both hands on the wheel. Also, it's important to note that even when your phone is locked with a passcode, Siri is usable without entering the code. That means that anyone could use your phone to send a text message, access your calendar, or make a call. You can disable this security flaw in the Settings menu, but bypassing the code is the default option.
The iPhone 4's 5-megapixel camera was already great--especially when you add a third party app--but the iPhone 4S' is significantly better. The 8-megapixel camera offers autofocus, flash, f/2.4 aperture lens, and a backside-illuminated CMOS sensor that allows 73 percent more light than the previous sensor and should deliver better low-light performance. A hybrid IR filter is also onboard for better color accuracy. Apple also claims the new camera performs 33 percent faster than the iPhone 4's camera, and the A5 processor has a built-in image processor that adds face detection and 26 percent better auto white balance.
From the start I noticed a difference in image quality over the iPhone 4's camera. Colors were brighter, and the focus was a little sharper with a bit less pixelation. Not surprisingly, the camera also does better in low light, though flash continues to be a little overpowering at times. Here's an in depth look at how the iPhone 4S' camera compares with the iPhone 4. And for more photo fun, Senior Editor Lori Grunin compared the iPhone 4S to the Canon PowerShot 100 HS.
The user experience is almost the same, from the tap-to-focus feature to the video toggle and the shutter control. You will, however, notice a new "Options" icon between the flash control and the button for switching between the cameras. Press it, and you'll find both the HDR feature and an option for adding gridlines to the viewfinder.
Thanks to iOS 5 (more on that later), you also get new choices for cropping and rotating your shots, red-eye reduction, and a single-tap color correction option. The red-eye reduction is a simple process that offered instantaneous and impressive results. Similarly, the single-tap color correction tool balances your colors and, in my tests, did indeed make the image look better. Though I welcome these additions, Apple is way too late to the photo-editing party, as this functionality has existed on basic phones for years. I'll take what I can get, but I'd love even more user control.
iOS 5 also adds several requested features to the camera app, making it much more like a point-and-shoot camera. You get a shortcut on the lock screen that will launch the camera immediately, even bypassing the lock code. A simple double-tap of the Home button brings up both the basic music controls (as before) and the camera icon in the lower right. You then can use the volume control to snap a photo. The picture is saved to your Camera Roll, but for security (having not used your access code) you'll only be able to delete the shot (keeping unwanted users from browsing your iPhone photos).
Videos also get a boost with the ability to shoot 1080p HD video clips at 30 frames per second and with video stabilization. Videos continue to be sharp with fluid movements and sound that matches the action on the screen.
AT&T's 4S differs from the Verizon and Sprint versions in one major way. While all three handsets have dual-mode (CDMA/GSM) chips inside, the CDMA functionality on AT&T's handset has been deactivated. Though it's an unusual arrangement (perhaps it was cost-saving measure), it makes no difference to you since there's no need for an AT&T cell phone to even connect to a CDMA network. So both at home and abroad, you'll use GSM just as you would on any other quad-band (850/900/8100/1900) world phone. It's worth noting, though, that unlike Sprint and Verizon who've promised to unlock the iPhone 4S' preloaded Micro-SIM card, AT&T will limit international GSM roaming to its specific partners.
Verizon's and Sprint's iPhones runs on each carrier's EV-DO Rev. A 3G network, which promise speeds of 600Kbps to 1,400Kbps and average upload speeds of 500Kbps to 800Kbps (actual performance will depend on your location and the carrier's network capacity at a given time). AT&T, however, is doing everything it can to boast that it has a faster HSDPA 14.4 network that's capable of reaching theoretical speeds of 14.4Mbps down, 5.8Mbps up (twice the speed of the iPhone 4, if anyone is counting). Note, however, that AT&T has taken some liberties with its marketing by also saying its iPhone 4S is compatible with even faster HSPA+ speeds. To really be classified as HSPA+, its iPhone 4S would technically need to be capable of reaching theoretical download speeds of 21Mbps, such as AT&T's Samsung Galaxy S II. At present, Apple's device isn't there yet.
The CDMA models still won't permit simultaneous voice and data transmission. That's a current limitation of the CDMA technology (see our Verizon iPhone 4 review for a more detailed explanation) and though new chips are coming, I'm thinking they'll arrive in the next model. So if you really need to be on the phone and surf the Web at the same time, then you should stick with AT&T.