My vote for used equipment goes to KEH in Atlanta, they are extreamly picky in there rating system. I can buy things in "excelent" condition which is the lowest rating before their bargen catagory, and I would swear that it was brand new right out of the box. I have been most impressed with their products and service.
As for Adorama, I have bought used from them before and I will not do that again. They sold me a used Contax RTS that was rated 8+ a while back. When it got to me it was missing the battery cover. So I went and bought a battery cover from a local repairman, and the camera worked fine, for about a month. Then the whole thing died.
They wouldn't take it back, and so I ended up giving the thing away because it wasn't worth it to have it repaired. I felt cheated and Adoroama lost a customer.