DEEFINITELY GO BUY IN PERSON THEN! You should handle the snake and see for yourself, or have the breeder handle it, to see if its snappy. I would avoid getting a very young hatchling, as they tend to be the most fearful. A subadult or an adult will be more mellow generally, but really you only know if you are in the snake's presence. I bought online, only because I want to breed, and I wanted a very specific, high quality rare morph from a reputable pro, and I wanted to browse hundreds of snakes using a search engine.
I don't care so much about bites, because I am very careful with handling, and I am 100% confident I can "tame" (a contested word around here it seems) a young snake that grows up with me.