Whether you prefer large or small cichlids, I’ve found that knowing what behavior you’re looking for in new fish doesn’t confine you to one category or the other. In other words, cichlid personalities don’t differ a whole lot based on the maximum size of the fish. Some dwarf species are just as aggressive and pugnacious as their larger cousins, such as the largest Cichla (peacock bass) or Crenicichla (pikes) species. There are also some very large but reasonably docile species.
Your first decision on what to keep shouldn’t center around what behavior you’re looking for. What cichlids you keep should be based primarily on one criteria – the size of the tank rather than the personality or behavior of the fish. Large cichlids, aggressive or not, don’t belong in small tanks and neither do a handful of small, aggressive cichlids. Even if you want to employ the density method to mitigate aggression among medium sized cichlids, the size of the tank should still dictate how many fish you put in it. Also, if you buy juveniles, know their maximum size so you can factor that in. Therefore, based on your available space and your budget, decide on the size of your tank(s) and then determine what you can put in them. Knowledgeable, experienced, and conscientious cichlid keepers will tell you the same thing.