There's actual brand fideliy artifacts, that give you neat stat bonuses for a certain manufacturer.
Back in Borderlands 1, I actually mained Eridian guns. They were clunky and inefficient , but I loved the feeling of wielding alien guns in a universe where everyone uses bullets. It made me feel like the protagonist in District 9.
In Borderlands 2, I'm loving Torgue weapons so far. Dual wielding 2 rocket miniguns is by far the most fun I've had in a FPS. I actually remember using this one for like 5-6 levels: