Hi, I was wondering if anyone has good advice to render high quality images of realistic CC4 characters for the content store?

Do you use iRay in general or perhaps render your product in another 3D app (Marmoset, Blender, etc.)?
I'm asking because no matter what light or IBL I'm using the iRay renders in CC4 don't look very good. I've seen some other products on the marketplace that have very professional-looking images. What would be your recommendations? I think rendering in an external app means having to deal with getting the shaders right.

Would really appreciate some hints and tips on this!
Thank you!