Another thumbs up for Power Director on the windows platform. I haven't found a format that won't edit yet, and believe you me I've tried to find one . Did have stability problems in the past, which caused it to crash quite a lot, but the foibles seem to have been ironed out with the latest versions (I'm using version 9).
On Linux, I find Openshot is very user friendly, and powerful.
A lot of these editors come with bells and whistles, and Power Director is no exception with a plethora of silly transitions and mickey mouse titling which I ignore completely. I stick with basic titling, usually white on black, simple fades and the occasional lap dissolve or a straight cut.
A couple of tracks for audio is usually sufficient for me. I remember the good old days of analogue video, where you had to contend with +/- 5 frames of editing accuracy (if you were lucky), a linear editing process and one dubbing track which was fairly low-fi, and annoying drop out on the tape. which would often ruin a decent shot. I remember it once took me the best part of a fortnight to edit a 5-minute film which had to be cut on dialogue. Nightmare.