The "features" in that video are a joke. Does anybody know if there are under the hood improvements in this version that would make upgrading worth the money?
Application Groups: you (or OmniGroup) can mark multiple apps with the same developer ID, and they can share files, use IPC/XPC directly, a shared file system location for user data, etc.
You can watch session 700 at WWDC 2012[1] that's I (poorly) summarized above.
I think OpenGL on OS X is also upgraded to 4.0 on ML, but I'm not sure. Siracusa's review at Ars (when published later today) will tell us if it's true or not.