@magicalclick: You can check out the ReadMe. It goes over all the changes from Beta 1 to Beta 2. To answer your question about frequency of changes, there are no new features (other than updates to /_Admin) or changes from Beta 2 to RTW.
I worked on both Oxite and Orchard. The ALT.NET's loud screaming unfortunately did affect Orchard a LOT. With Oxite, we went back and fixed the parts up that made sense (not everything they complained about, but lots of it). It was our first MVC app,
which I'll also throw out is STILL running sites just fine today despite "bad" programming practices. Orchard is the polar opposite and has used "good" programming practices from day 1. We'll see how it goes. Note, I am no longer on the Orchard team for
my day job.