Hi PaQ,
Nvil has the greatest ever functionality of creasing edges. Modo with those tools of weight tension is like a kid near NVil :) Also I do not meat such a tools in any other modellers. So NVil is the best.
Check this video: I showed here how it works:



Personaly I always use this crease commands and never creas edges by creating supporting loops.

Nvil can export in .obj and .dae.
Unfortunately as I know these formats do not support this kind of information like creased edges, so you can not save it in .obj. But if you need model in .obj just export subdivided model.
And for sure all creased edges information is saved in NVil native format .vws.