After seeing some really impressive stuff, I cannot wait to test this stuff on my own! I mean seriously, a retail Xbox One as a devkit? That is so amazing I can't even comprehend it!
If it's finally released, awesome. That's a major reason why I decided to get an Xbox One over PS4. I made games with XNA on the previous system, so I'm excited to finally get to start developing on the Xbox One.
XNA was nice and fun to program with, but I think Unity is generally a better game engine, it's still C#/.NET development, the base version of Unity is pretty open and free now, and you're not locked into "The Microsoft Platform" with it.
So overall I'm pretty satisfied. I could probably even quickly port some of the XNA code over with minimal changes (not the graphics, unfortunately. Assumed a fixed size 2D viewport for all my layout and animation code, which was a mistake).