The more they've eaten before you buy them the better. My first snake (a pastel) had only eaten 2-3 times before I took her home, and that was a big mistake for being a newbie. Errors on my part led her to not eat for the first 2-3 weeks I had her, I was scared. I would go through it again cuz she's awesome, but I just wish I had bought her and had them feed her a few more times before I brought her home.

It's likely you won't encounter the same error I did as I was given bad information from the breeder. But, I would still go with a BP that has eaten at least 4 times.