I use Avidemux all the time. One of the better editors.
The irony of linux and Ogg-Video, hardly any applications support it for editing, AVidemux being one of them that doesn't.
The greatest problem I have with AV editing is audio sync. In avidemux I have to shift the audio forward or behind to get sync. It would be nice if the editor could calculate the discrepencies for you and set the values.
Kdenlive is the most elaborate but I dislike its lockon frame size before you start adding videos. As in with kdenlive you have to set your project resolution size then add videos that will suit or convert. It would be better if that was more flexible as it really punishes you when you goto rendering your project and find it's all incompatibile. The rendering options are awful too, ery un-user-friendly. Kdenlive is renowned for bugs too.