There will be on OSX native app as well as the Classic version so Carrara (and RDS) will run in either OS. It took me about a month of working with Carrara to get used to it after being familiar with RDS. The hardest part was forceing mtself to use Carrara when it seemed so much easier in RDS. That being said, the core of the app is still the same with 3 major changes: UI, speed of render and shaders. I'd still recommend Carrara for the price VS preformance issue.