I tried the 3.0 release candidate earlier. Aesthetics wise, it seems very customizable, but personally, I liked how the 2.5 UI looked more.
In terms of functionality, also very customizable (moreso then 2.5 i think), but I had problems accessing the UD settings (which BD mentioned in the release notes). Quite a few very cool and handy new features, but certain apps like facebook, gmail, and youtube just flat out refused to work. All my attempts to run them just resulted in them getting forced closed over and over again. I couldnt find the torch app but it existed as a widget instead. I found no problems with the camera and camcorder (other then a bit of lag using the latter). I did however run into issues trying to access the gallery (invalid file path message). Was able to get to it another way though. Couldn't find the CPU overclockng features either.
I ended up just restoring back to 2.5. I know all these things will probably be fixed in the final release but for now 2.5 works better for me.