I like the look and feel of MC6, so I'll probably like X2 as well. I can only go for Essentials at this time as I don't think I need all the other stuff for primarily voice-over work, but having loops and other rack-type modules would be useful for development.
I wonder what the Apple/Pro Tools guy thought of x2 it after listening to demos mentioned in an above post. That bit wasn't mentioned. It'd be good to see that they converted to Sonar.