I suppose you could have a bp out for that long too, as long as the temps and the environment were good. I personally have never had mine out for that amount of time, but, like Leah said, it should be fine if you work up to it.
The main thing to me is the significant size difference. RTBs grow much faster than bps, and you will need a much larger enclosure for an adult. I know you already said that space wasn't an issue, and as long as you are truly aware of how big they can get and that you'll have to be picking up a snake that could potentially weigh around 30-40 lbs, then it's all good. They are both awesome snakes... boas are more curious, bps are usually more chill... so it really comes down to your personal preference as far as overall look, feel and temperament
Good luck, and I can't wait to see pics of whatever you choose!!