Okay, after all the bitching about how Mission Control is dumbed down compared to Spaces and Exposé and how it does not fit my sophisticated professional workflow, I decided - just for a change - to use it for some time and see if I can live with it. Much to my surprise, I discovered that it's actually quite usable... or, to be precise, it would be usable if not for a couple of very annoying bugs. First of all, the Z-order of application windows is completely messed up when using Spaces. For example, I have two windows (Safari and Finder) on Space 1 and another window (Mail) on Space 2. When I switch from Safari to Mail using Cmd+Tab, everything is ok. But when I switch back to Safari (once again, using Cmd+Tab), I get back to Space 1, Safari gets keyboard focus, but its window all of a sudden is located beneath the Finder window, not above it. This is extremely annoying and makes Spaces completely unusable. The second bug is even more serious. It can probably lead to data loss. When rearranging Spaces (adding and removing virtual desktops), Pages got stuck in the middle of nowhere. The application was running and even responding to keyboard commands, but I just could not get its window to show. It also refused to quit when I pressed Cmd+Q and the only way to get it out of this weird state was to force quit it. I tried to reproduce this bug and discovered that it happens surprisingly often - roughly 1 time out of 100. Will report those issues to Apple. Hope they will be fixed in 10.7.1.