Hey Soundwave! I got a question similar to this on my Facebook page, wasn't sure if it was you but then I realized others may be interested in the answer so ill post the same reply here...  

The black versions will look pretty good without paint, but you might find them to be "matte black" as opposed to the gloss black of Nero Rex. They use a dye to color the parts. That said, it would be fairly easy to add an Acrylic paint to the parts for a nicer sheen, avoiding the joint areas (which will be matte black) for maximum durability. I have some videos on how to paint Shapeways parts on YouTube (under Echotransformer). Some people are satisfied just using a paint marker which is super easy! In the end I suggest ordering black, and then decide what to paint and how...