There's nothing wrong with random mutts unless your breeding for a particular breed in which case you need a rooster and hens of the same pure breed you're breeding for. My philosophy is to keep the calmest and most gentle rooster as you don't want to breed aggression into your flock. Based on what you've said about the temperament of your roosters, and since you're leaning toward Smokey, it sounds to me like he's probably the best rooster to keep.
