Personally, if this is your first boa, I would recommend a Dumerils. I adore mine. I had BCI first, but after getting my Dum, I can see why they are the perfect first boa. She has the best personality ever and is just realy easy to work with and handle. The Dums can be a little tricky to get started feeding for you though - its their only downside. My female didn't eat the entire first month I had her. But she eats every week now! Usually, once they get turned on to food, there's no turning them off.
BCI are another great choice. A male won't be any larger than a Dum and will be slightly less heavy-bodied. They have wonderful personalities and are eating machines!
Both BCC and Rainbows can be a bit more temperamental and touchier with husbandry. I really would not recommend either of these for a first boa. Not saying it can't work, but in general, it's not recommended.![]()