I took these pictures awhile back to show the size difference between an adult female BP and an adult female Red Tail. The Red Tail is about six feet in these pics and the BP is real close to three feet.
Six feet may seem like a lot, but it's really not all that bad, especially if you have experience with BPs on the larger end of the spectrum. And you have to remember that RTB males usually top out at six feet (though some DO get bigger).
Boas make very rewarding pets, IMHO. They can be so sweet, very curious snakes. I wouldn't trade my Kinkers for anything!Just remember... the snake poo is directly proportional to the size of their meal LOL