I've bought two performers, one E320. two silver kettles, a smoky Joe and a 18.5 WSM.I also bought 5 1000-2000 Geneses to flip. Using common sense as stated in the posts above you should be fine. All of the grills I bought I gave a thorough inspection and asked lots of questions. The nearest was two blocks away( WSM) and the furthest was a 250 mile RT to Phoenix for the E320 which is NG so they are harder to find so I made the trip.
All of them with the exception of the Genesis were a little clean up and good to go. The one performer was brand new, assembled but never used, that was my best find $75. If you're buying a summit or a later model Genesis look carefully for rust in the firebox on the Summit and rust in the cabinet of the genesis especially the floor of the cabinet.