I have been using iMovie for the Mac for nearly ten years. I last used it this morning, for final effects and publishing of a football game video I’ve edited.
I use MPEG Streamclip for editing video, Handbrake for file conversion and iMovie for audio/video effects and publishing to iTunes or a file.
All free software.
I used to use iMovie, before they revamped it (presumably to “make it easier”) and turned it into a completely different program that I could never figure out.