Customer service is really everything if you are any kind of business, large or small. My first BP purchase was mail order from a "big breeder" and it went fine, though I didn't like not getting to see the exact snake I got before purchase (though it turned out to be just fine and beautiful).
My second BP I purchased from a small breeder just recently (as it was a much more expensive BP than my first). I had found two breeders that had snakes I like (both from online classifieds). I had two specific snakes I was looking for at the time: Kingspin or Coral Glow. The first breeder had listed a Kingspin and I sent him a text message as it was getting a bit late in the evening. That night, he pulled his ad for the Kingspin, so I figured it had sold. A few hours later, he sent me a text listing two others he had that were not what I asked for and their prices, which were higher than the Kingspin I had been looking at. Still assuming the one I wanted had sold, I told him they were out of my price range and thanked him and never heard from him again. Overall the communication was terse and he didn't seem interested in talking to me or getting to know what I was looking for. Perhaps he was just bad with text messages, but at this point it was after 10pm and I didn't want to call or bug him anymore. Funny thing is, the next day I see his classified ad for the Kingspin re-listed (though at that point I had already contacted the other breeder and made a deal).
Lesson learned, I called and left a message for the second breeder and he called me back within an hour. We talked a bit and he was happy to discuss the lineage and temperament of the snake I was looking at (a Coral Glow female). He also went out of his way to meet up with me and deliver the snake the next day. Overall, it was an excellent experience and I had no issues giving him the money (he also discounted his listed price as it had included shipping -- something he didn't have to do as I was thinking shipping was extra). Number two was a great breeder and now I'm happy to recommend him to anyone looking for a BP. Number one I don't really have much to say about as he didn't seem very interested in selling me a snake (which is odd as I made it very clear I had cash and was looking to buy).
Perhaps had I called the first breeder from the start, communication would have been better and I could have just asked if he had the Kingspin available. That's my lesson learned. Either way, I was very happy the other one I contacted and got one of the two snakes on my wishlist (still want a Kingspin, though planning to wait a while).