It just depends on what you trying to accomplish. Are you wanting a beautiful show tank or are you wanting breed them?
If you want a nice show tank, go with a all male tank.
If you want to breed a species you need to keep them separate, so they don't interbreed. This will not make a very good show tank since their will more than likely be one nice male and a few half colored up males, and you can expect plenty of aggression. I prefer to just have one male in a species tank.