I doubt it's the model's geometry that's at fault here. I begun experimenting with poser since Friday, but I understand that it isn't fully compatible with 3Ds files, which does makes sense in a way.
If importing as .obj results at the same quality, perhaps you need to check at the textures and see if the vendor has included high quality ones, which you have to apply via the materials panel (meaning he hasn't made any MAT poses for them). A screenshot of your renders with the props you mention would certainly help us get a better idea about what's going on.