Deskbar- It's great that it's now installed by default, but where did the option for integrating the whole utility into the panel go?
Compiz-Fusion. I kind of wish that they would have left this alone until next release. Compiz-Fusion has had some serious bugs until release 0.6.0, and definitely was not ready for the limelight in 0.5.2. Unfortunately, while the compiz core packages were installed at 0.6.0, many pieces of fusion were still at 0.5.2, (most annoyingly compiz config settings manager, which was frankly unusable at that point). Furthermore, the old feisty third party repos' packages are uncompatable with the new gutsy repos' packages, making CCSM 0.6.0 frustratingly difficult to install. Yes, compiz works perfectly well without the new CCSM, but it is far less customizable.
All in all, the compiz issues are my only real frustration, but enough so as to make Gutsy on par at best with my previous Feisty setup, even with the other new features.
My desktop. Dock is Avant Window Navigator