Here are my first impressions, for what it's worth....
System setup = super easy! Easiest console set up in a while. Linked right up to my profile.
System UI = Very nice and clean, easy to navigate. Minor irks trying to find the system settings, but I found it. Also, silly little things like trying to find the download queue and after I purchased and downloaded the Ultra ed. of KI, I'll be darned if I can find KI Classic! I don't know if it's is it's own game or in the menu of KI. I'll chalk this up to getting familiar with the system and the new dash.
Killer Instinct = To hell with the reviews, this game is bad ass! I had a lot of fun with this and I think it's pretty deep, even with only 6 fighters right now. I can't wait for the next two fighters and a dedicated arcade mode.
Ryse = Again, reviews be damned, I really like this game! Granted I'm only in chapter two, but I really enjoy the combat, the visuals are eye-melting and the story has me intrigued. It helped that I read the three free web comics and watched the trailers. I think it'll help to get into the story if you understand who/what Damocles is.
Seriously to sit there, playing Ryse, and pan the camera is just mind-boggling. It feels like you are playing one of Square Enix's old crazy hi-def, super polished final fantasy trailers. It's really something and if you want to be sold on the "promise" of next gen, this game will do it.
Oh, and I feel compelled to say no sign of any kind of system failure or drive problems. At all.