It takes a little getting used to. The iMovie interface tendencies I have are tough to break, but the multi-track editing and simple process is actually quite nice under Linux. It takes some unlearning if you are really used to the iMovie stuff, but once you get going, it flows well. Here is a picture of some editing direct from .MTS files off a Canon HD camera. It’s great to just get in and start working with the video as opposed to having to import with iMovie. Multiple tracks, markers and cuts work well.
More on the OpenShot Video Editor at http://www.openshotvideo.com/