Just to throw a curve ball here, if you're looking for an alternative node-based compositor, there is a hidden compositor in the free open source 3D modeling program Blender. It has some surprising capabilities. I posted about this a while back, have a look here:
http://forums.creativecow.net/readpost/14/865056
All it requires is that you put some time into it, and think outside of the box, of course...