I got one when sellout.woot had the refurb. So far, a pretty-OK internet radio alarm clock with an OK Youtube app that I use to catch up on my subscriptions while I'm waking up. I also have the MyEbay Watch List app and Woot! apps loaded. The Woot! app isn't Woot-off aware, but each time it cycles to that app it will show the current item, so you do get some hint one is going on when it changes at times other than midnight. A lot times I used to have to fire off my netbook late nights are taken care of with those two apps plus the built-in weather and Youtube apps. The 'night mode' clock is pretty nice, and I like being able to hit a button to blank the screen entirely with the power save if the extra light bugs me, and can bring it back by touching anywhere on the screen for quick checks of the time.
Built-in Youtube app wise, you can search, see what's popular, view your subscriptions, etc. Better than most Youtube apps I've seen, though, there's no master list of new videos from subscriptions, so I have to go to each user, then sort by date posted to get the new videos from them. Youtube is unfortunately limited to 480P max(no selection on quality) from what I've seen, even though Youtube HD rips play fine from USB sticks. Other streaming video apps don't seem to be limited to 480P, as watching (and pausing to get closer look at details) HD trailers on Flixster look amazing.
Alarm wise, it's decent. A bit disappointing that I can't seem to get it start a Pandora station as the alarm, something that I'd hoped it could do. It'll play from a small selection of included alarm sounds, as well as stuff like streaming music videos in a very limited genre selection seeming chosen at random, Dr. Dobbs Journal, and regular .m3u or streaming audio, but not Pandora or Slacker.
USB support is kinda tacked on, as it didn't even any way to be used for quite a while after this was released from what I've seen. Don't expect it do much more than play MPEG 4 videos and MP3 audio off USB mass-storage right now. It's still being updated with new firmware, so maybe that will change in the future.
The video playback off USB, when MPEG 4 and in the proper container -- .MP4, .mov (including H.264) or WMV 9 -- is pretty good. It can handle up to 1080p and scale it down to it's screen res very well from what I've seen. I mostly save stuff in 720P, so most of my testing was with that, which all looked awesome except an older WMV codec file.
The photo viewing app is very limited, only really useful to make it a digital photo frame. No controls beyond flicking the photos left or right for previous/next, and continues on to the next photo after a pre-set period of time (when you select all photos). No zoom or rotation capabilities.
In theory it should be hackable, the source code to the OS is here: http://products.sel.sony.com/opensource/source_dash.shtml It seems to respond to Chumby scripts placed on a Flesh drive, but I haven't played with it much.