Borderlands: Utterly mindless entertainment. It might just be the perfect example of a shoot-n-loot. OTOH, constantly upgrading weapons and deciding which trade-offs are worth it is fun. Play through as a different character, but it is still mindless. It is just different things to upgrade.
Don't get me wrong. It is fun. Just don't expect much of a story..... or plot....... or character development..... or much of anything beyond things to shoot and things to shoot them with.