Well, in my case it all came down to size. I have a five year old, with one on the way (I also have an 11, and a 15 year old too LOL), and I wanted them to be able to handle them. Also I like their temperament (the snake's, not the kid's LOL). They eat well, hardly ever bite, and don't require a lot of room. Having said all that, I have my sights set on a Reticulated Python later on when the kiddies are all bigger!
Cheers
GL