Amazing choice and one of my faves as well!
We're a BP forum, but a lot of folks on here have a boa or two as well. As far as personality goes, I've found boas to be more interactive. They typically aren't as shy as a BP, and can be a lot of fun for kids to grow with. Of course they do get large - some of them VERY large. Island boas are typically the smaller versions - Crawl Cay and Caulker Cay boas being some of the smallest http://www.cuttingedgeherp.com/islandcayboas.html
If you're going for pretty colors though... stick with the BPs. They can also be friendly and make great pets, and come in VAST numbers of different patterns and shades, they just tend to be a little more shy.