KDENlive is an open source, complete video editor for Linux.
Beta versions are available for Windows and Mac.
Ranked in these QuestionsQuestion Ranking
Pro Open Source
Kdenlive is licensed under GPLv2, and built on top of other open source projects like FFmpeg.
Pro Surpisingly complete
Although this editor is not up with the top of the professional pack of editors, it certainly packs a powerful punch, and should provide enough features for amateur montages, ranging from alpha manipulation, to multiple audio and video live track editing.
Con Timeline cursor is not working
Timeline cursor is not working well on Kubuntu, very difficult to use it. You have to switch all the time between project monitor and clip monitor to get it work.
Con Doesn't support multi frame-rate video editing
When you choose the mixed frame rate option, your video with 60 fps will be broken (slow down and trimmed).