I've always had Buggy's or Prerunners and we call our XP4 a buggy. Its what my 3 year old calls it, so that is what we call it.
And for those offended by the word "Buggy" you should only wish it was called a Buggy! UTV should be the bad word as AB1595 gave UTV's their own classification and laws. UTV's must wear helmets and so on, yet in a Buggy you are free to do as you please.
And for those who have had to describe it as a Rhino, I'm with you. I have had to do the same thing when people have asked what I have. I say a UTV or Polaris 4 seater and they look complexed. I say its like a Rhino and they go "OK I know what your talking about".