I'm using Fedora 15 with KDE, which is running wonderfully. I had to upgrade one package to get KDE to play well, but I think that's fixed in Fedora 16 which is current.
I have not had any issues with the space bar--my only problem has been with the left shift key.
I have to add that the only gestures I've actually used are multiple finger scrolling, pressing with multiple fingers and circular scrolling (which is pretty cool). I don't have zooming--it tends to annoy me more often than not, so I don't know if that works well (or at all) on Linux.
I have not had any issues with the space bar--my only problem has been with the left shift key.
I have to add that the only gestures I've actually used are multiple finger scrolling, pressing with multiple fingers and circular scrolling (which is pretty cool). I don't have zooming--it tends to annoy me more often than not, so I don't know if that works well (or at all) on Linux.