It's hard to argue against Piper but my favorite on the list is DiBiase. I think Ted had the best career out of all of them and he never held a singles championship in WWF.
No doubt Piper was a bigger mainstream star though, he had that angle with Cyndi Lauper and main evented the first Wrestlemania.
DiBiase and then Jake were my two most favorite wrestlers out of the 3 in that order. But Rowdy Roddy Piper's impact at that time is undeniable. He was Hogan's Lex Luthor. Even when I started watching regularly in late '87 and he was slowing down he was still always on top or right behind the top of the card and getting crazy reactions. I remember one time back when we used to bring the toys to school for trading or playing during lunchtime and shit most people brought his figure so we all cancelled each other out lol.