I have had zero issues (beyond normal OS quirks) with Snow Leopard so far on 5 different Macs (1st gen Unibody MPB, 2007 17" MBP, 1st gen MacBook, 2007 Mac Mini and 1st gen Aluminum iMac) all seeing a variety of different uses (including development and virtualization on my machine). It was stable at .0 and it's still stable. In addition to that, it runs beautifully on my Hackintosh!
I dunno if the whiners just like to whine or what, but I just don't see the problems I hear on these forums. I didn't when I installed on the day of release.
I do want to mention that on every machine I have set up, I've done a clean install and reinstallation of all software because I distrust major OS upgrades. It's the first time Mail.app has been stable since I started using OS X.