I voted all male, but I think it depends on the person. I enjoy watching the "natural" behavior of breeding groups. My wife could care less about that and is only interested in color and different shapes and what not. I have both. My display tank the in the living room is all male and visitors very much enjoy it. When I show them the mixed groups tank, they are much less enthusiastic. And some people are only happy with a tank if it has a pirate ship in it...