I honestly don’t like it much – always makes me think of the sandwich. And I know two guys who spell it Ruben, and they’re always asked “like the sandwich?” when they tell people their name (and then they have to spell it).
My cousins name is Reuben Matthew. He’s in his thirties and I’ve never met another Reuben! I agree that it is very much a classic and under used name, so that gives it a little bit of an unusual flare!