Be as discriminating about the breeder as you would be about the snake. Knowledgeable, helpful breeders with contact information are the best. Question those who don't know much about their animals.
I was at a show last month and asked a guy about his Savu pythons, just out of curiousity. He replied, "Oh I just got these because they were a good deal... I dont know much about them." Nice.
Another guy had spotted pythons, which I have been strongly considering buying. He was the only guy at the show with any spotteds. I asked him a few basic questions and his answered reasonably, but he had an unusual tone, as though my questions were bothersome. I asked for a business card and he said he didn't have one. I asked if he had an e-mail address and he said "yeah, but uh, you'd have to write it down or something". He obviously didn't want to be available. Earlier he had also told me "F*** ball pythons man, these are way better." Classy.
Last year I got my Ball python from a breeder named Tom Furr. He gave me his card, told me to e-mail him any time. Really nice guy, very knowledgeable. Those are the people you do business with. And the snake? A beautiful, active, healthy female normal BP.