I started off compositing in After Effects, but have since shifted over to Nuke. I was reluctant to learn another piece of software at first because I had already had to learn how to use Massive, RenderMan for Maya, IQ, Motion Builder and others for this film. But I'm glad I gave Nuke a shot, because it has turned out to be a lightweight, fast and intuitive package.
I like rendering in layers, it gives me a lot more control in the composite.
- Character (from multipass render):
Working in 16-bit color is also very useful, as it expands the range within which you can color correct the image without creating artifacts.