I just upgraded my site with Community Server 2.1 Beta 2, which was published yesterday.
The upgrade went pretty good. I only had to re-compile my custom Akismet spam rule and Ken Robertson's Qgyen.ExtendedUrlMapping module (which source code he fortunately published as well.)
Though I'll stay with the default skin until its final release, I'd like to mention that there are four new blog skins included in Beta 2. Awesome work, Jaxon.