For basic cutting and arranging clips and stuff, they're all relatively easy to use. My friend who had never used an editing software other than imovie figured out premiere cs5 pretty easily, I mean all you have to do is drag footage into the project panel, and then drag it into the timeline and cut it how you want. Using keyframes and color correcting are more advanced but the basic layout of the programs are really simple and easy to figure out. If you can't figure somethign out just look up some tutorials on it.
Premiere and fcp are equally simple imo, but after effects and speedgrade and other programs are more complicated and harder to figure out
