likes:
-sliding back through web histories/desktops/document pages, gives you a great ability to "peek" at content without actually having to go there
-the first time i logged onto gmail in safari, lion detected it and asked me if i wanted to use that account for mail/calendar, and with one click i had it set up!
dislikes:
-resume seems buggy. i opened a text file on my nas and then closed it before quitting textedit, yet now whenever i have text edit running, it shows that file in the minimized area of the app expose (an annoyance). worse, when i'm at a different location from my nas, it seems to crash text edit because it can't figure out where the open file went. finally, going to system preferences and turning off resume/recent documents doesn't change the behaviour. same thing happens with quicktime, too.
-mission control needs serious work. when you are in a full screen app and you invoke it, the active space is still the full screen app in the spaces area, but visually it shows you your primary desktop in the expose area. so when you swipe, it moves from your primary desktop to the space next to the fullscreen app, which spatially (ha, ironic) makes no sense. i also dislike that the peeking and rubber band effects which are present everywhere else are omitted here where they are needed most to orient yourself. and thats to say nothing of the lack of being able to re-arrange spaces to best suit your workflow. overall, mission control feels needlessly half-baked.
those are my thoughts so far