KDEnLive: Most Promising, But Not Quite There Yet
KDEnLive 0.7.5 was released a few days ago, so I installed it on my Ubuntu machine to see how the app has been progressed since the last time I tried it. KDEnLive is the most actively developed, and easiest to use Linux video editor. Its UI resembles Sony Vegas in many ways; if you know how to use Vegas, you won't have trouble with KDEnLive.