I've just upgraded my hard drive so I've done a fresh install with 10.6.0 and I'm trying to work out what I need to do to get back to 10.6.3.
The major disadvantage I've come across is that you can't run Safari 5 on 10.6.0. I miss the Reader facility and the extensions especially the 'Cleaner Youtube' extension which enabled me to download videos in mp4 format.
I'd like to upgrade to 10.6.6 or 10.6.7 - mostly because an increasing number of developers are only offering software via the Mac App Store.