Pros Unknown. Luckily I did some research before I took the Mavericks update. You should too.
Cons Local syncing has been disabled
Summary I'm writing this as a warning to Mac OSX users. The new Mavericks update takes away the ability for users to sync calendars, contacts or anything else via USB cable. If you take the Mavericks update, you will be forced to use iCloud for all syncing. That creates a host of problems. Google the issue and decide for yourself. Privacy is a huge issue. Not being able to sync overseas without incurring huge data bills is another. Lack of ability to decide how YOU control YOUR data is another. Be warned. And if like me and many others you think Apple should change its decision to disable local syncing, let Apple know through their feedback option.
Pros Calendar ease of use - The Calendar upgrades are the only thing that stand out for me.
Cons NO SYNCING Service
Summary I have had Macs since the early 1990"s. I have told anyone who asked over the years that I would always prefer a Mac. The incredible ease of use. The security and dependability are tops in the industry. I have never bought a mac I didn't like. I honestly sit here after days of research rethinking my opinion.
No syncing service is the worst decision that Apple could make. I am angry that they have the audacity to require me to upload my information to servers. No, I don't have highly sensitive information, but it is my information to do with as I please. This a hassle that I don't need.
I also find it interesting that they are one of those companies that does not respond to customer complaints. Complaints should be as good to a company as compliments. They let you know what your customers want. From what I am reading across the internet there are more complaints about the syncing services than there are compliments for the Calendar and other useful upgrades.
Pros Increased speed
Extended battery life
Great features for improved productivity
Cons I haven't found anything I don't like about the system yet.
Summary I upgraded my mid 2007 15" MacBook Pro 2.2 Ghz intel core two duo to Mavericks from 10.6.8. The most noticeable difference is the speed. My biggest concern when I was deciding on whether or not to update was if my computer could handle it because of its age and it blew me away. The second most noticeable difference is the features. I can now do all the multi-touch movements with my old track pad (the one with the physical button), receive notifications for emails, calandra events and social media in the upper right side of the screen. The third was the extended life of the battery. My old battery would normally last about an hour and this improved it by at least two times. Apple shot themselves in the foot because I was going to buy a new MacBook Pro with retina display in January or February and now I think I'm going to wait another year and make that decision in 2015. Mavericks is the system I've been waiting for.
Pros Other features are very nice. If you don't want to print anything then this is a good upgrade.
Cons Do you ever print using an HP printer or a Brother printer--too bad. You CAN'T DO IT ANY MORE unless you spend many hours trouble shooting, booting in safe mode, repairing permissions and jumping through a lot of arcane hoops. All doable -- but why
Summary Don't take the risk until Apple Fixes the ProblemsIT NOW WORKS--
Updated on Feb 13, 2014
My Star Rating is Now 3* (4-1 for difficulty/lack of user ease)
Since writing this review I was able to get Mavericks to print to both an HP8500 and a Brother 2820. I need to uninstall both printers then go to Brother website and install an updated driver. At this point the Brother still didn't work so I uninstalled it again. Then I went to Apple's Software Update--I had done this several times and no updates were available. BUT after UNinstalling the printers a printer software update was available. This cured all prior problems. Based on this my recommendation is:
1) Uninstall all printer(s)
2) Use Mac Software Update
3) Reinstall the printer(s)
This should fix the problem.
Pros Great power saving features and more efficient CPU usage.
Cons Worthless Microsoft-like features like Notifications, Maps, iBook, Messaging, and a bunch of other unnecessary crap that fills HD space. No express card support so it's impossible to run peripherals like external hard drives. Workflow is total crap.
Summary Get rid of it. This is the Vista of OS X. Stick with Mountain Lion.