Borderlands 1: Hyperion, Maliwan, Dahl.
Borderlands 2: Jakobs, Maliwan, then Vladof
Jakobs used to be of limited use in BL1 (revolvers mostly) due to the horrid reload times and iffy accuracy (sans revolvers), but they've really come into their own in BL2, due in part to the new Slag mechanic enhancing their high base damage, and the overall nerfing of the other elemental effects.
Maliwan's only gimmick is that their weapons have elemental effects. Apart from that, their weapons don't suffer from any of the bullshit that plagues most of the other manufacturer's.
Their sniper rifles, SMGs, and pistols are all accurate and effective for the most part.
Vladof is basically the new Dahl in BL2. Their weapons aren't especially awful anymore either.
I love their machine pistols, and Sniper Rifles when I can get one above Green grade. Their assault rifles lack stopping power, but that's due to the MASSIVE nerf to Combat Rifles from BL1; I don't get it.
Their Machine-Pistols have better stats all-around than most of their rifles: Magazine, Damage, Accuracy and reload.
Dahl is right behind Vladof, for their fine SMGs and Assault Rifles, but their Burst-fire Sniper Rifles piss me off to no end. No, really, I like burst-fire weaponry, but sniper ammo is far too limited in BL2 for it to be practical (and little to no ammo regen to fix that problem).
Tediore: Their Rocket Launchers are amazingly useful.
Not much else to say; their regular performance is middling, and the gimmick wastes ammo.
Torgue: Power. Everything.
Their Rocket Launchers are horribly inaccurate, but they make up for it with tenacity.
Their Gyrojet weaponry is hit-or-miss. I'm currently rocking a rather powerful Torgue Pistol, but only as a last-resort sidearm, or opener against enemies carrying physical shields.
Bandit: Lol. No.
Hyperion weaponry in BL2 is largely TERRIBLE since their accuracy formula is reversed.
Especially Hyperion SMGs, which are mostly unusable unless you like this uncomfortable JUTTER-JUMP every time you pull the trigger.
The problem is that the first shot is the one that counts the most, since it's aimed at a critical location. Missing that shot every time is NOT worth the "advantage" of having to spam ammo by the truckload hitting a now-moving target.
(NOTE: I do not take a manufacturer's Legendary weapons into account for any of these placements because all legendary weapons are exceptional in some way or another. Either in power, gimmick, or weirdness, not just practicality.)