Agreed, RTB's are not giants as defined in snakes. Giants are burms, retics, afrocks, condas... snakes that grow in excess of fifteen feet and weigh over a 100 lbs.

There is no question in my mind... go with the boa! They are an excellent entrance into the world of larger snakes without dropping you into the deep end. They are also very fun snakes to care for, usually very calm, always curious and outgoing...

But hey, I'm biased!