Aside from the built-in light, Kobo's done some interesting things with the fonts on the device. It's added new fonts that are optimized for the screen's higher resolution, and you can really customize how the text is displayed on the screen, with the ability to change the margins and justification. I didn't find the contrast incredibly good -- the letters aren't inky black but more of a dark gray -- but the text is sharp at smaller font sizes, which is nice. That's where the higher resolution is a big boost; that, and cover images.
The other unique customization feature is the ability to adjust how often the screen refreshes, aka flashes, to clear the ghosting inherent to e-ink. You can have it refresh every page turn or less often, down to every six page turns. For those who don't like the flashing, you'll want to stick with six. But if you don't mind the flashing and are more irritated by the ghosting artifacts, you can set it to refresh more frequently.
Kobo's Reading Life social reading features, and Kobo Picks, which makes reading recommendations based on your feedback and preferences, are also included, along with standard features such as a built-in dictionary with 13 different language options. Yes, the Glo is an international device, so you can change its "base" language to one of several options. You can also highlight words and sentences and add annotations. Standard fare for an e-reader these days, but it's there.
As far as what files the Glo accepts, it's considered an "open" device with support for EPUB files with or without DRM copy protection. You can buy EPUB e-books from any EPUB-compatible store (so not Apple, not Amazon) so long as you install Adobe Digital Editions on your computer. The same goes for library e-books: they have to be manually transferred over to your device. In contrast, many libraries now allow you to send files directly to other e-readers such as the Kindle.
Kobo does have apps for Android and iOS, so you can sync books bought via the Kobo Store across multiple devices just as you can with the Nook, Kindle, and Sony Reader. However, as noted, the Kobo Store simply isn't on par with the Kindle or Nook e-book stores and Kobo doesn't have an e-book lending option or anything like Amazon Kindle Lending library, which allows Prime members to check out certain e-books for free (one book title per month). Amazon also has other small but useful features such as "Send to Kindle" plug-ins for browsers that allow you to send articles directly to your Kindle.
Overall, the Glo's performance was decent enough. As I said, the touch screen is responsive, maybe not quite on par with the Paperwhite's but close, and page turns were relatively zippy. As with all e-ink devices, there's some lag, and extras such as the built-in Web browser work but not well.
As I said in the intro, the light is pretty impressive and can be adjusted with an onscreen slider. At its brightest setting, it's very bright in a dark room, so you'll want to turn it down to midlevel or maybe even lower. While there's a touch of cloudiness at the bottom of the screen where the LEDs are, it's no worse than what you'll see with the Paperwhite and the uniformity is quite good -- the light splays out pretty smoothly across the screen. The color seems a touch different than Paperwhite (it's less white), but I found the hue fine for reading.
As for battery life, Kobo says you can get up to 55 hours of continuous use with the light on and a month of battery life with Wi-Fi and the light turned off. The Kindle and Nook claim numbers twice that with Wi-Fi and the light off. In other words, the Glo isn't beating the competition in terms of performance, but it's more or less in the same ballpark.
The Kobo Glo is a bit of a challenge to rate. From a hardware standpoint it seems very solid, with an impressive built-in light and a high-resolution display that allows for crisper text and is especially useful for reading at smaller font sizes. I particularly liked the interface and some of the extra customization options for font rendering and screen refreshes. But while the Kobo Store certainly has a good selection of books, it doesn't offer the breadth of books offered by Amazon or Barnes & Noble. Also, both Amazon's and Barnes & Noble's stores are simply better, with a more appealing interface and a much greater number of user opinions posted for each book.
At least in the U.S., even as good as the hardware is, the Kobo is a little hard to recommend over the $119 Kindle Paperwhite with Special Offers (yes, it has ads) or the $119 Barnes & Noble Nook Simple Touch with GlowLight. But certainly overseas where Kobo is at its strongest and expanding rapidly -- or for those in the U.S. who want to mix and match EPUB stores -- this is a very good e-reader option that will hopefully continue to improve over time as Kobo tweaks its store and adds new features and performance enhancements.