I've been using xmonad on arch linux for five months now and it's been amazing. Rock solid stability and no wasted space on the screen, no wasted time arranging windows. Multi-monitor support is second to none. I can't go back.
My tools of choice for over two years now. I've had a very similar experience, xmonad is simply the most stable (read: consistent) window manger I've used.
At work I need to use a mac, however, and SizeUp has been good to me. Can't wait to try this one.
