Hardtack makes a good bulletsponge, and he's certainly not useless, but by mid game you'll probably want a tank with a little more speed, damage, and crowd control. He is, however, ideal for sending out on global conflict missions, and his teleharpoon can give you some interesting tactical options against single heavy opponents. He starts make a good showing again in late- to post- game, where LEGION tech allows him to stun enemies with his 360 melee attack, and have a chance at disrupting any enemies who damage him. This make him good for clutch situations that might simply overwhelm another agent. (eg dealing with shocktroopers and a plasma turret, while snipetroopers cluster above).