After going to the AT&T store (or any cell phone Store) for the first time last week, I would NEVER let these guys touch my phone. I was kinda amazed at the sales people. They were fixing some guys iPhone and that looked too scary. maybe I just always had good luck and never had something that I could not fix myself, but I just feel a lot more comfortable fixing things myself.
I must say that I have lucky and never had to have my phone repaired. ::knock on wood::
If so I would rather call on the phone and tell them whats wrong. Have them ship me a device rather than have some one try and tinker with it. Granted it would entail reloading everything onto the newer device again but it's a grain of sand on the beach in the grand scheme of things.