I have an innie. And it hates me. Probably a combination of the dry air in my house but the simplest stretch causes a paper cut like crack on one corner by my belly button and I hate it so muchhhhh.
I don't think I've ever met someone with an outie. Though belly buttons creep me out so I prefer not seeing them. xD
I used to be super skinny as a kid, and I had an outie. When I grew up and filled in a bit, I developed an innie, which I personally like better (plus I have my belly button pierced, which would look weird with an outie I think).