So I've had a while to play around with the beta of the New XBOX Experience (ie the new ui) and it's really cool. The entire thing just seems more fluid than the original one with the 'blades' interface. I think it'll go over really well.
The blades are actually still around for all those that love them. they exist in the new guide that pops up when you hit the '360' button. This I'm not so crazy about. It seems like like there wasn't much thought put into the look of it. The functionality is there all right, it works perfectly well, but the look just seems a bit... off. The plain blue toned screen looks out of place surrounded by the slick flow of the NXE.
In the end it's a very small complaint but still.
Oh and Avatars are super happy fun time. Avatars > Miis. Better looking and more of a presence on the dash. Kudos to MS for this.