I tend to lean more towards well started youngsters, or yearlings. You know they've been feeding, as babies can sometimes be a little more difficult. Also. the sweetest snake in my collection is also my biggest. I adopted her as a 2.5 year old, 1600g adult. She's sweet as pie, and great around kids. Two years later, I adopted a second female, that was about 1000g, and she's also sweet. And add to the fact that both are my best breeders, laying 10-12 eggs.With adults, I think it could go either way. If you're just looking to breed, and want some animals with size, I can totally understand how temperament wouldn't be as important. I bought a few adult females in the past that were downright nasty!! However, if you're looking for a sweet natured snake, or a pet quality animal, I'd definately go with adoption. You can't go wrong with an animal that's already used to being handled.