In addition to the above, it depends on if you care to get a morph or not. For the most part, rescues are all adult normals with maybe the occassional pastel or inexpensive single gene. The pros of a good rescue adult is if it's already been feeding on f/t rats, you won't have issues. And you can ask about the snake's feeding response, which I'd want a snake who has rarely missed an f/t meal, if I went with rescue.

While for breeder hatchlings, most breeders feed live mice or rat fuzzies, and you may happen to get a snake with a hard time switching to f/t or a hard time switching to rats. You can always discuss with the breeder what you're looking for, but there are no for sures with hatchlings eating live.