On my Mac I've used iMovie, GoPro, Final Cut Pro. I keep coming back to Premiere Elements. It's a familiar editor, does a nice job of managing compression, handles my 4K videos well and most importantly he's been stable. It's has good titling, a good suite of transitions, and manages lighting and color management well.
You can buy Premiere Elements bundled with Photoshop Elements for something like $150. I used to use the full versions of both, but Premiere used to be very buggy, and I abandoned the full versions when Adobe put them in the Creative Cloud. As it turns out, I haven't felt limited by using the "Elements" version of either program.
