Two weeks ago, I wrote a review about Desktop effects by default in Gutsy - how Compiz Fusion enhances Ubuntu's desktop of version 7.10. I published it by the time the beta was still fresh. We have passed the release candidate by now, so this is pretty much the actual state of affairs. Time to see what has been fixed (and what not) or generally improved.
The following quotes are from the above mentioned review.
The only problem that hasn't been resolved, is that you can't change the number of desktops in the panel's Workspace Switcher.
You would have to do that in gconf or turn off the effects, change them in the context menu of the workspace switcher and turn the effects back on.
That was an annoying issue and pretty urgent, because ccsm (CompizConfig Settings Manager) is not installed by default in Gutsy.