I have 3 columbian boas(BCI). Happy as can be with them. The normal color phase is fairly inexpensive and I have a side of me that really likes the normal color phase snakes, including normal colored ball pythons.
I think young boas including columbians and dumerils can be kinda flighty and crawl around alot. As they mature they'll chill more and become better shoulder pets, etc..
I say columbian, BUT, don't have any experience with dumerils. I do like the skin patterns on the dumerils!
I think the columbians have a better showing appeal because I like watching mine climb and hang out on branches in their cages. OK, this is making me want to build some new(bigger, taller) enclosures for my boas!