On paper, Hulkbuster, but practically, Sentinel. Hulkbuster's unreliable heavy is his downfall, you just don't feel safe playing him. Sentinel is super tanky, has great damage, heal block/armour break and power drain resistance along with regen and special spam. So in gameplay, Sentinel does more than Unreliable-Heavy-BusterAlthough for me, I hate Sentinel's clunky animations and can't stand playing him, sorry where-worm @Werewrym