I was using the free Gopro Studio program, for both video and timelapse editing, very simple to use but I found it a a bit buggy, even with a faster i7 windows machine. Had also used the old Windows Movie Maker. So I went to Adobe Premiere Elements, been very good so far. But, of course, this is all on Windows machines.
I intend shooting some fishing Gopro footage tomorrow in Protune, will see how that works out for editing on Premiere.