Don't want to scare you or anything, but just keep in mind that as with any wild animal, some are a little more high strung than others. I have a common BCI who is mostly tame and not a problem, but he has his moments and does get startled fairly easy. Which sometimes results in a defensive bite. I pretty much only take him out when everyone else is in bed and the house has quieted down for the night because of this. Makes it easier on both of us. He's still a great snake though, just something to keep in mind.
As far as the 10ft boa, a BCC can hit that size, so if size is an issue, you gotta make sure you're getting a BCI. They're not always easy to tell apart just by looking, although I'm sure some more experienced boa people probably can.