Personally, I would hold out for a Bco. If you are comfortable with their potential size and are capable of caring for a very large snake (enclosures & food), then I'd say definitely wait until you've seen both and take your time to think about it. I'm a huge Bci fan also, CA's are great boas, I'm just a big believer in not rushing big decisions. If you see a few Bco's and decide you prefer CA's, then you can go back and buy the CA you had your eye on. But really, you can't go wrong with any of the boa constrictors.