I have been using Beryl on Feisty with a dual monitor setup at work for just over a week now, and I can say that it is fast and fun to use. The stability has improved markedly as have all the tools for configuration and tweaking.
Unfortunately a nvidia bug means that I must use a slower rendering path and there are some bugs with blank windows. I’m hoping Nvidia fixes this soon because apart from that Beryl is absolutely beautiful.
I believe this is going to be a big step for linux moving forward. I definitely have a nicer desktop at work than the windows guys running Vista or even the Mac guys. Combine this with Dell selling linux and PC’s and maybe we are approaching a very happy place indeed. All that is needed is a large corporation (Novell perhaps?) hand-holding users and saying hey look here is linux its shiny and its easy to use. Maybe we will get somewhere. Maybe.