I'm a big fan of this series as me & a relative plan this split-screen (and occasionally online) on our PS3 consoles. This is a FPS RPG in a open world format (post apocalypse) with a wide variety of unique enemies to hunt and tons of loot.
The multiplayer online supports upto 4 players in a game which makes it a blast to play online. The leveling-up, the DLC missions etc. make this a very long campaign with replayability into eternity.
Frankly, I cant choose between 1 & 2 as both have been incredible. If you have friends to play with, you will have a blast. If you don't, just go online and hook-up to other's games to make new "Borderland friends". Enjoy!