Caseless since launch day and the only worn part is the edge at the top. Everything else in mint condition. Yes, some people had black iPhones with defective anodizing coatings that turned to s*&t in just two weeks but I believe they've since corrected that manufacturing defect.
In any case, worn edge is pretty much normal with anodizing coating (from what I've seen with watches, etc.) and can be temporarily touched up prior to selling.
What I'm impressed with, though, is how scratch free the exposed apple logo on the back is to this day, unlike the first three generation iPhones where the apple logo got scratched to hell. The iPhone 4/4S apple logo was immune as it sat behind the glass.