We've received a large number of bug reports in the past week from people testing the 0.9 beta-3 and we're going to need a further week to get everything through the doors and ship the most stable version of MediaCore to-date. We originally were planning on launching this week, but we've decided to hold off until next week to finish off the final few details.
For now, beta-3 is very stable and upgrading to 0.9-final should be pretty easy.
Thanks for hanging in there with us! We're very excited about 0.9 and getting it into your hands.