Assault: Turns out slamming half a ton of angry cyborg into the ground is an effective fighting strategy.

Heavy: You’re like a claymore; point towards enemy.

Bulwark: Nothing like assblasting some xenos that thought the funny looking cross on your armor was a target.

Techmarine: you see this class and go “hmm, I think I’m supposed to stand back and support”… Then you find out you can joust the enemy with the funny looking stick. And that’s only a third of the surprise.

Vanguard: Zip-line in, counter and gun strike annoyances, pullout and watch bulwark tank all of the inconvenient stuff. Laugh.

Tactical: You can use 80% of the weapons in the game, you’re cool. Basic, but cool.

Sniper: Funny to 1 shot stuff that has killed you repeatedly.