I thought the gameplay was fantastic and I loved the huge amount of weapons that were put into the game. The thing I didn't like was the lack of characters that actually talked and the story was kind of weak.
I loved Borderlands, the visuals are really cool. I really like the loot aspect. Checking every single gun to see if it improves yours, and excited finding chests etc... Fantastic game, I really hope a 2nd one is coming.
Sometimes, you just have to ditch deep storytelling and just make a game...fun. This is one of those games. Great choice to put in Diablo-style weapons management and the 4 basic classes make it easy to get in. In addition, the art direction was perfect...a realistic look would have ruined the feel.