I upgraded recently to OSX Lion and I am using Apple’s Magic Trackpad with it to fully enjoy all gestures Lion offers (I have 2009 MacBook). I am slowly learning to use all the gestures to change pages and programmes etc. with Aperture it seems to be a different story, however.
With Magic Trackpad I have to double click Aperture’s adjustment sliders to “lock” them. After that I am able to move the sliders. Same thing with keyword list; I have to double click the keyword to move it out from the list on the photo. To release the lock I have click again. That’s quite annoying. With Magic Mouse I just click once with left button and keep the button down and am able to move sliders and keywords right away (normal dragging with a mouse). There is an option for “three finger dragging” in the Magic Trackpad preferences but I would like to use three fingers for changing the programs (I find using four fingers little bit awkward). Maybe it is so that I have to use Magic Mouse when using Aperture and Magic Trackpad in other occasions.