Thought I'd drop in my experiences of the last 5 days playing Borderlands on the 360.
First of all, this is a grind-loot game in the vein of Diablo. If that does not get you going, you will not like this game. There is a story but it's not very deep, and the quests are merely a mechanism to move you around the various dungeons. Imagine it as an FPS Diablo set in a futuristic world and it's fairly accurate. There are no built-up areas and the world is sparsely populated. The bulk of the game is set in an open desert area with various dungeons in different formats ie Cave/Undeground Complex and so on.
The main drive is combat grind and loot drops. Grind to level up and always trying to get that special weapon. Co-op is awesome, although I would not play with randoms due to the fact that anyone can pickup the loot so it can be stolen easily so you want to playing with people that won't pickup a shotgun they can't use well just because it has good stats and can be sold for a good price. Co-op is hard, a lot harder than SP as the game levels to account for the extra players. Overall the game is quite hard, you don't want to be taking on missions anymore than 1 level above your character as otherwise you will get your rear end whipped.
Enemies are nicely varied, and bosses are great fun. All in it's a cracking game but you have to like this type of game, if you don't you just won't get it.
