UWindows looked nice and ran smoothly...it was organized, but it was just an interface. If you have to make settings changes on the fly (In the game), the new interface is 10 times faster for getting into the menus, making the change and getting back to the game.
I don't see what all the fuss is about, background screenies not withstanding, I think the 2k4 demo interface is smart and easy to use.
Overall, it's an issue the vast majority of people playing now don't care about and Dr. SiN is on the record as saying the Uwindows is absolutely not coming back and we better come to terms with that, so the subject is moot (or m00t! as the case may be
).