Magix Movie Edit Pro and Magix Movie Edit Pro MX Plus.
The current version of this product is Magix Movie Edit Pro 2013. Unfortunately, the initial release was super buggy. A major update fixed most of the bugs but I continue to encounter many problems with 3D editing, such as losing synchronization between the audio and video when working with paired tracks, and some oddities in their user interface not saving results properly.
Because of that, I edit 3D using Magix Movie Edit Pro MX Plus (version 18). That version is reliable and has fewer "issues" in the user interface. So I use it for editing. But its sort of slow if you want to play your timeline and its quite slow to encode into MP4.
MEP2013 is a much faster - but too buggy to edit with. So I edit with version 18, save a copy of the project file, and then open the project file copy in MEP2013. There, I can play out my 3D video clips in near real time using my low end Nvidia graphics card and CUDA. MEP2013 also puts the GPU to work in its mp4 encoding and this too is faster.
MEP has one very nice feature - and that is its ability to synchronize your left and right clips by having MEP automatically analyze the audio track waveforms and use that to auto synch the tracks.
I'll have more to say about MEP and Sony Vegas Movie Studio in some future posts.