I've been putting off the update to 11.04 from 10.10, is it relatively pain free?
I blame the lockup/windowing issues completely on Unity and I've had more success with the system since I've switched to the classic Ubuntu desktop. My current Linux desktop is running 10.10 and it will stay that way for the foreseeable future (perhaps until 11.10). I have a new sandy bridge desktop coming in next week and I'm undecided as to what I will be installing on that system.
Unity isn't perfect yet, but I'm confident the UI team are heading in a decent direction.
Regarding the upgrade itself, yes - it's as easy as usual (click, click, click, .... done).