So far my experience with ViaCAD is rather positive. It definitely doesn't crash on me. It doesn't run
on Win7 though, at least on my computer. In case I want to edit some Moi models with ViaCad , I export
as "step", "sat" should work ok too.

You might also want to check out Alibre, they have a $99 version, but I'm not sure right now about import/
export capabilities.