I love Rolf. He's one of my top-5 villagers in the whole series. He currently lives in my New Leaf town, but I wouldn't mind if he moved into some of my other towns too.
Rolf is nice, though I've never had him in any of my towns. I think I would like him a lot if he ever was a resident, but for now he just happens to exist and that is the extent of my attachment to him.
Rolf matches my Rune Factory themed town, so if I can't get all my dreamies from natrual cycling, I'll have him move in with my card. He's the closet thing to a Malm claw there is.