I think the PC is better simply because enemies don't strafe dodge like humans.The weapons hit so different in campaign.
The mauler is super fun.
It's basically like a stronger pistol with bullet drop, It takes some skill to use but because of that its super satisfying to one shot dudes in the head with it.
It may actually be useful in multiplayer now that I know how to use it.
Also the pulse carbine, I think the bullets magnetize to the enemies more in campaign making it more useful (or they are just more static making them easier to hit) but it kind of wrecks.
If you strafe dodge left and right Vs an Elite with a PC, they can't hit you for shit even on Legendary lol.