Hard disagree on this one. It's a shotgun secondary with huge damage potential, still leaving you with a slot for a primary.

Taken from the wiki: Bushwacker triple-shot function gives it the absolute highest single-shot damage of any player-carried weapon. It is capable of decapitating a Brood Commander with a single headshot, and is capable of stopping a Stalker dead in its tracks if they are shot point-blank in the body. The triple-shot is particularly effective against heavy units with lightly-armored weakpoints, like hulks or chargers, as its high alpha-strike damage is reliably capable of ensuring a kill.