I dont think it's fair to classify all JCPs as snappy monsters. I know several BRB owners who have the same to say about theirs. Each snake has it's own "personality" so one cant really generalize.
Carpet babies (and BRB) can be snappy when young, but usually can mellow out with age and handling. Personally, I've looked at both and think they're gorgeous snakes..I just dont know if I have the time to keep up with the husbandry requirements for the BRB. I like it simple
That's why I have a BP!
Cant go wrong with either..personally, I'd go with the JCP. Actually, I'd go for it's close relative, the Irian Jaya Carpet Python..gorgeous beyond words if you get a nice specimen!