After seeing a fellow founder at a Y Combinator dinner this week running the GM seed of Mac OS X Lion without any issues I ended up installing it on my MacBook Pro.
I only ran into a few issues with my development environment. I had to install XCode 4.1, update rvm and ruby 1.9.2, uninstall imagemagick and the rmagick gem, then reinstall imagemagick and run bundle update for my app. It's working great now. That being said, I'm a tad disappointed with Lion. There was so much hype around it and the only real discernible changes are: a sleeker Mail.app, Mission Control (Launchpad.. meh) and an improved Spotlight (cursor down files and a preview pops up).
Then again I've only been using it for 8 hours. I'll provide an update when I have more time to blog and when I've spent more time with Lion.
What do you think of Lion so far if you've installed it?