I've purchased two iPhones in the past from Orchard. But this was my first time selling through their service. It could not have been easier. They sent me all the shipping materials I needed, I sent them my phone and four weeks later (on the exact date they promised), the money was deposited into my bank account.
Sure, I might have been able to get a slightly higher price by placing my own online ad, fielding offers and then meeting strangers in a parking lot for the handoff. But I would never buy a used phone from someone I didn't know, so why would I sell one that way?