Kdenlive does an adequate job, but, from my limited experience with it, has a large learning curve. I have used it on several projects. It has good sound mixing and hooks to all of the features in ffmpeg and other video editing libraries. As far as features go, it compares well with the professional video editors available on Windows and Mac, but isn’t as polished, and tends to crash on very complex projects, as do some others. I wouldn’t use any of the open-source video editors for professional work, and I would prefer Mac over Windows, but I’m a dedicated Linux user, and, on Linux, kdenlive comes the closest to being “ready for prime time.”

I mostly use OpenShot, and have for ten years. OpenShot started out simple, and changed radically after being ported to Windows, with some good features added, and some favorite ones (like audio muting for a complete track) taken away. OpenShot is, for the most part, a lot easier to use than kdenlive, but, like kdenlive, tends to crash a lot and exibit quirks when working on very large projects (most of my projects use 40 or more clips with a raw run time of 20 minutes or more, edited down to 5–10 minutes of finished video). I sometimes use avconv when I need to crop or flip clips,or use other effects that aren’t on the OpenShot menu, and import the edited version into OpenShot.

Shotcut is also becoming popular, and is simple to use, but I haven’t used it. What I have works, adequately.

Blender is largely a 3D animation tool, but can be used for editing video clips as well, since version 2.8, and is as close to a professional product as open source gets. OpenShot uses Blender for animated titles and special effects, and Inkscape for static titles. Blender is also a complex tool with which I have only passing experience, since I don’t use the animation features.

Bottom line: If I had realized how complex my amateur video production would become, I would have spent more time learning the fine points of kdenlive, and learned enough about Blender to incorporate it into my everyday toolbox. Kdenlive is still my fallback when OpenShot puts out a buggy version upgrade, but OpenShot lets me put together an adequate travel/action video with no frills in a couple of hours, with simple titles.