I have all mine set to 5 ball. My thinking was similar to most above. It's more fun for my kids... However, that means I'm playing FIVE substantially longer balls when we play together. I like it, but it may make for exponentially longer games, as you unlock more of the modes.
It's an easy switch if you don't like it.
5 ball is for fun at home with your family.
3 ball is for people who hate children, and want a divorce.