There are a lot of new features in this one, which are pretty cool, one is the beat/sample slicer... check out their homepage, and then the forum to read more about it. All it comes down to at the end of the day, is the feeling you get from it.
But the beta round is over and there are no more slots available. If there is another round of beta testing downloads, it will be for the RC and that will be public without having to own 6.
(Sorry guys, I thought this was the public one, but I was logged in at the moment of downloading, and did not realize this!)
Ill post here if I happen to know when they post the new beta round.