Summary: The weakest of the DLC for the first Borderlands game. This DLC is definitely intended for co-op as playing alone feels like an overwhelming waste of time. Repetitive wave after wave of bad guys makes this one mediocre at best.
Summary: As many others have stated, this DLC takes probably the most lacking part of Borderlands (i.e. the shooting) and puts it in the spotlight. With no experience or equipment to gain, the core of the game is removed and make Moxxi's an unsatisfying DLC.
Summary: This is the perfect example of how NOT to do DLC, it adds nothing enjoyable and has no real value other than a way to play through a crappy Horde mode clone with your friends, it gives you three arenas and each one has 5 rounds each consisting of 5 waves and each wave is the same every time you play...
Summary: Nowhere near as good as the original game or the zombie expansion. It will take a good few hours to finish but you are just in one of three arenas killing wave after wave of bad guys. I played through one of the arenas last night with 3 buddies and it took about 2 hours.
Summary: It's worth the money. It adds hours of game. 3 arena's, 25 waves a piece broken down into 5 rounds the 1st time around. Then you do them again with the difficulty up and 100 waves each in 20 rounds.