I produced an iMovie presentation this weekend. I was actually fairly suprised at the simplicitty of doing what I wanted to do. *Most* things were in obvious places, and if they weren't, it didn't take too long to hunt and peck for it. Some of the featuers I really liked was the Audio Ducking. This is where you can have one audio track volume lower, while the other stays the same. Really nice if you're doing Voice Overlays onto Music backround. Another thing which was pretty nice was the ability to take a picture, and freeze it within the movie. Was nice to be able to comment at the end of a small clip., without having the need for some lame blank screen to look at.
Overall, I'd give the program a 9.5/10. Easy, and nice to use. A definate plus to owning a Mac.