I like to use Motion. It can do way more than iMovie, but doesn't come near Final Cut Pro. Its only $50 (compared to $300 of FCP) which is a great compromise between iMovie and FCP. I wish I could get get Final Cut Pro.
I use Sony Vegas 12, (cause I only upgrade every other update) final cut pro X and premiere at work. If you are looking to move from one of the less professional programs like moviemaker or iMovie, Vegas and Final cut pro are nice next steps. Both have a similar style that is very intuitive and easy to learn but have a ton of professional options under the hood. Personally I love Vegas and work exclusively in that on a pc over premiere. But, I think if you need to do power editing and work with effects and complex titling especially with after effects, it is better to use premiere. If you have to link several sources of video together, for a multi-camera effect, I think final cut pro does that better than anything else without using a plug in.
It is a pretty comprehensive tool that does everything I need at the moment.
I will be looking for a different tool for time lapse though as powerdirector seems to have a limit of 2500 images imported to a single project. That is only 20 minutes of real time PER individual project at .5sec per image (only option on my GoPro).
I use Joyoshare Media Cutter when I first come to video editing field, which is very good at cutting, trimming, splitting and joining video and audio clips without reencoding at a fast speed. Other editing features such as special effects, watermarks insertion, etc. are also included. Still happy with it. Great option for newbies. https://www.joyoshare.com/video-cutter-win/
For those of us who grew up editing on Adobe Premiere, you can download a free, retired Premiere CS2 video editor. Just search for Adobe products retired. You won't get any support but what do you want for nothing. Anyone who hates icon based editors and prefer timeline based, this is for you.