There is no "in brief" explanation. You select a component based on the application. Voltages, speed, current consumption and the list goes on. Even at that TTL (Transistor Transistor Logic) today is not anything like the TTL of less than a decade ago. You may want to give this a read but I don't see a simple brief answer to your question. Each family has its good and bad features so again it comes back to choosing components for their intended application taking into consideration a mountain of variables.