What is the quickest way to compare the DPS of two weapons?

I've been playing Borderlands 2 coop, which means that there isn't always a lot of time to evaluate loot before deciding to pick it up or equip it.

What is the fastest way to compare the damage output of two weapons? Does the game provide any indication of which items are an upgrade without having to contrast all of the item's stats?

There is no single DPS number that I have seen (only about 45 minutes play time), much like Borderlands. Instead, you've got to look at multiple stats and make a judgement call based on personal preferences. As with Borderlands, I expect that taking things for a spin will be really important when it's a close call.

In addition to the stats you see when you mouse over a weapon, there are at least a few hidden stats: Zoom Level (present in Borderlands 1), recoil, and stability. Shooting down a sight impacts DPS, obviously, and stability is a major factor there. Recoil will affect dps when firing rapidly/burst.

It's not always desirable to shoot as fast as possible (even when not using scopes/iron sights). I think it's just impractical to include a DPS calculation. I do wish Borderlands weapon "cards" showed more stats though. Stability is really important for sniping, for example.

I am 30 hours into the game. There is a way, it's quick and dirty and doesn't cover all aspects, but it's better than nothing :

Multiply the damage by the attack speed. This is not a silver bullet, but it gives you a pretty good idea of what makes 80% of the dps.

For example if it's a 100 damage, 2 fire rate sniper rifle versus a 75 damage, 4 fire rate sniper rifle, it boils down to 200 dps versus 300 dps giving the advantage to the second one.

That being said, other factors enter in a gun's performance that are not shown in the stats. A big one for me is the bullet speed... some weapons have great damage but the bullet are so slow (or behave like grenades) so you don't want to use them. Another factor is quickback, or the quality of the visor. So use this rule of thumb i posted, but for your main weapon always test the new one before you sell the old.