The perfect game for those who love to shoot and loot with their friends!
I managed to put about 150 hours into this game all by myself (DLCs included). The reason: guns, guns and guns. Borderlands loot system is highly addictive to anyone whose obsessed with collecting weapons and then looting to find even better ones. I wouldn't have replayed the story so many times if it weren't for the fact that I loved being able to kill an enemy and find a new, exciting and unique item every time, it added freshness to a story that got somewhat stale after the first playthrough.
Aside from collecting Borderlands has some great RPG elements in that it lets you pick one of 4 unique classes with 3 different skill trees within that class, each level up you get a skill point which you can use to buy new skills or upgrade old ones.
Another great aspect of the game was comedy, you can tell that this is not the kind of game that strives to be taken seriously, but wants to make you laugh while you blast off bandits heads. Many of the friends and enemies you encounter along your journey are very entertaining and it makes the game a lot of fun to play. (Many of the DLCs were even more hilarious).
The place where Borderlands really shines though is Co-op online play, specifically with a few friends. Killing enemies, then racing to loot weapons first (then arguing over who gets what) is an absolute blast and it makes the game worth playing again and again.
Overall, fun, funny and addicting (especially if you love collecting new weapons!), better with 3 friends and not for someone whose looking for a compelling story. Also DLCs really add to the experience (General Knoxx's Armory makes up for the disappointing ending).