No doubt about Lion using more ram... I check istat every few hours or so, I used to always have 6.something free, now I see 4.something free...
When using cinema4d, AE and VM fusion I've noticed I'm running out...never did before.
I love lion but think its better suited to a macbook air user/light users than people who work with creative packages.
The absence of spaces I miss, I had a good set up... mission control isn't cutting the mustard.
The default invert scrolling is pure crazy in 3D packages.
As above, it seems to hog resources more.... Still a pleasant OS to use, just going in another direction... I wish there was a classic mode!