Poorly crafted add-on with many annoying traits.
You have to drive everywhere. No fast-travel, just you, a road, and tons of stuff in the way of where you are trying to get to. The enemies in the way aren't even worth killing for loot of experience - they're just there to keep you in your vehicle and stop low level folks from getting too far. The two new vehicles, well, they're useless.
In the original, you could go all the way across the map and enter an area through a transition - there, you could log out, and be saved in your present spot. Not in this DLC you can't. Whenever you leave and log off, you will always respawn back in T-Bone Junction. Stupid, just plain stupid.
Yes, you have a loot spree in Knoxx's armory, but it only happens twice per character, and you're not guaranteed any really good weapons. Crawmerax's lair, yes it's fun, but same thing, no guaranteed good stuff. Idiotic.
It's nice there is a new level cap, but other than continuation of high level characters, this DLC doesn't really bring anything to the table. Only one or two "dungeon" type places to go through, and the rest is open areas not worth exploring, and more driving.
Last annoyance: Lance soldiers everywhere - it gets really boring fighting the same highly armored guys over and over. If you've outplayed Borderlands and have $10 to burn, go for it.