I had a friend in a class with a 521, she was on Portico! (the horror!) So I got her an SD and fixed up everything.
I have three acquaintances with 521's, a friend who used to have one. I saw a couple 920's in my school. Friend's mom has a 920.
Someone lost a 521 a few months ago, it was posted around a bit.
I was crossing the street and this car turns in front of me, the passenger had a 521 in plain view.
My sister has a 521, almost sold my other sister on a 925, but she needed a special medical related app. She hasn't gotten a new phone though.
Haven't seen any 520's or higher end ones like the Icon and 1520 in person yet oddly.