From my experience boas are much more active when out of cage and quicker! They are more apt to throw a coil if they're not happy with you than a BP.

A BP has more of a 'small snake' temperament. They are more afraid and apt to ball up if afraid than try to constrict/eat you.

A boa constrictor has the 'big snake' temperament. If they don't like what you're doing, they can do something about it, and they know it.