No such thing as a best clan. Just clans that are better than others in certain game modes. This all depends on player's type of gameplay.
You guys gotta quit asking "Who the best clan? Who the best character? How do you make clintz fast? How do you level up fast? etc." It comes from experience and preference, my dear kiddos
Actually making clintz fast is survivor and level up fast in DM so those are easily answerable, best character is situational but most people would say Jackie Cr as an 8/6 4* SOA and attack manip its a solid choice, Best clan is the only truly hard one to answer.
So Ask as much as you want I don't mind my answers won't change much