I bought stuff from him a least five times. Had to email / call a couple times to finalize order. Never got an bad attitude, but I would send him a list of what I wanted with part #s and what the current prices where.
At the end of the email asked for a total with what was in stock and shipping.
Was told by him outright two things: Keep the order small / simple and if you have ordered with before, give him your customer # first.
I would also recommend getting a catalog from him and before ordering check this page first: