Mountain Lion and PS CS6??
I think it works better on ML, I found Lion a bit buggy. I teach digital photo and did a lot of testing with both CS6 and LR4 and have not found any problems. I encourage all my students to upgrade right away from Lion to Mt. Lion. Now from 10.6 to Mt. Lion, you need to do a lot of checking to make sure your plug ins will all work, etc.