KDENlive is an open source, complete video editor for Linux.
Beta versions are available for Windows and Mac.
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Pros

Pro Open Source
Kdenlive is licensed under GPLv2, and built on top of other open source projects like FFmpeg.
Pro Works great as an audio editor
Audio is edited in the same way as video, which makes it one of the best audio editors.
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.
Pro Its great for learn the basics of video-editing
Pro Subtitles included
Cons
Con It's laggy and freezes, with some chance of crashing
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 Dose not work well in Windows
They do not support windows well like other distribution. You will face a lot of problems.
Con No hardware acceleration
If you don't have a CPU that's good for video encoding, the render time can be quite bad.
Con Does not have good distribution channel
You have to go to their website to get newest version, does not auto update via package manager.
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).
(This con might be just misunderstanding of how to do video editing and production from the user who typed in).
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