I use Blender's VSE a lot
. It's remarkably flexible, with new features added regularly as Blender continues to grow. The drawback is that it is integrated as part of Blender's whole 3D modeling/rendering/animation product, and that environment can be challenging to master. But once you get the basics down, you'll not only be able to use the VSE as a non-linear editor, but you'll be able to integrate 3D elements and composite an unlimited range of effects.
Oh! I nearly forgot. Blender is essentially platform independent. That means you can easily move your project files from Linux to Mac to Windows with minimal maintenance.