Transparency thus far has been an issue from the reports I've read. I have not heard of the actual head textures not transferring -- unless, perhaps, you have several textures applied to them (for example, a skin, then an eye makeup, a bump, and a transparency, etc). the mtl file format that carries that info over is sorta limited as it can only transfer a certain number of texturing elements.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)