Yeah I'm not sure I love Mission Control, and full screen mode definitely has its issues, but I used Spaces for years and it insurmountable problems (windows disappearing, difficulty moving windows/apps around). Likewise, Exposé was almost useless to me with the volume of windows I had.

Mission Control has its issues, but it already seems much more powerful. Four finger swipe and control arrow integration makes it at least usable. I'm still figuring out how space reorganization works, but I'm at least as productive as I was with SL Spaces.