I've been playing with the ICS ROM that DHacker is running, that's based on CyanogenMod 9. I use it as a daily driver right now, and minus a few bugs and things they haven't gotten working yet (hardware acceleration, flash, and video/panorama) the UI is definitely worth the upgrade alone. Even if you don't like the new Blur on ICS (I think it's just fine), if they update the kernel for ICS, then all the ICS Roms will run much nicer. I've noticed even though there's some hangups from this still being beta software, that I can get through things much faster on ICS than I can on GB. Using GB now just feels clunky, and a lot of the stuff just feels like it doesn't work correctly.
If you don't believe me, try it for yourself. If you're not willing to try ICS, well then you're waiting. It's coming, whether you like it or not, so you better be ready to use it.