Are you running 11.04 beta2? I've been running it for months now and I LOVE Unity. I installed on my wife's machine, and while she doesn't love it (she really doesn't care one way or another about computers etc etc) she appreciates it in many ways. Though, the best way I can describe my wife's interaction with Unity is she gets less annoyed with it than she does/did with our iMac. True story.
Unity quickly became part of my workflow and improved it greatly. Super-W, Super-# are awesome, Dash is good (not great) and I like that something is built-in to the system that allows me to do basic searching etc (I hope this improves, but initial pass is really quite good). My workflow feels more fluid and solid w/ Unity, and I feel more comfortable, and hence, more productive than when I was in OSX just a short while ago.
And stability is something that is hard for me to gauge as I've been running since January on my test machine and beta1 on my main machine without too much problem. I get some quirks here and there, but nothing drastic. I'm running it on three machines: a mac mini, a lenovo t61p and a lenovo t60p. The t60p is the least responsive (naturally) and that is mostly b/c the ATI drivers are not as good as Nvidia's. The mini and t61p are nvidia and after installing those drivers everything works great.
And to compare, I used a Gnome3 live CD for several days trying to decide if I wanted to install something with Gnome3 (most likely Ubuntu w/ Gnome3 if that was the case, tbh...Ubuntu packaging makes it worth it alone) and while I think Gnome3 is a good release, it can't really compare to Unity. I like where Gnome3 is going, but I don't see it as something that directly competes with Unity at the moment.
I think Unity has a ways to go, but if you compare Unity in 11.04 to, say, OSX when it first came out...by god man, Unity is lightyears ahead in usability an consistency. People tend to forget how rough OSX was for a couple of releases. Apple has their act together now, but it took some time. And I LOVE something like Unity existing on Linux and being FOSS...pushing boundaries...