People put clothes on their poser figures??   Yeah, you can do that in Blender.  OBJ is the way to go.

Incidently, there have been problems with Blender and vertex order in the past for creating morph targets.  You may have to use a different script than the built-in obj import/export scripts.  Things also may not go into groups the way Poser likes them, either, I've had to manually edit that in an obj file before.  I'm not sure if that's still true in the most recent version of Blender, but it's something to keep in mind if you have problems.