gave it a try, but got rid of it pretty quick...
A few problems i ran into was that it was unresponsive, with choppy animation and delayed reaction. Second was that using my scroll wheel to cycle through the windows, i would scroll 3 windows at a time (yes, i have it set to scroll 3 lines per tick, and i intend to keep that setting-I'm able to scroll through flip3d's windows one at a time via the scrollwheel). and finally, i have a mouse button bound to flip3d. when i try to rebind smartflip's activation to the default flip3d key, my mouse button would activate both flip3d and smartflip... made for some interesting results.
I'm not a big fan flip3d myself, and wish microsoft followed expose's suit a little better instead of trying to show off their 3d features. maybe i'll give it another shot later, but the performance issues (flip3d is silky smooth), and the flip3d conflicts was a big, big turn off for me