Experience

ARGO: Experience is also better when you kill a higher tier tank than your own. Also if you shoot a tank that someone else basically beat almost to death, That player and not you will get the lions share of Exp for that kill even if your the one who put the finishing touch on it. But, If you really want to get some extra quick exp, put hits on a bigger tank even if you don't kill it if your hitting "and damaging" many tanks in a battle you will gain exp and sometimes even a Confederate badge.