Not what it could have or should have been.
First off, if you're more of a big-guns and power-armour kind of player, you'll be disappointed to know you'll have to leave most of your stuff behind (you can only take 75lbs of stuff with you). This immediately makes the DLC worse for some players.
You'll be greeted at the start by an annoying bunch of people you couldn't care less about. It's just as well that they die 5 minutes into the DLC. Eventually, you'll be met by someone even more annoying - Follows-Chalk. Poorly acted and thought out, you'll really want to kill him. To make matters worse, more characters are very like him throughout the DLC.
Eventually, you'll meet Joshua Graham. He's not as impressive as he should be, considering what he's been through. He'll get you to do a few easy tasks before the battle.
Unfortunately, the battle, which could have been quite impressive, is terrible. There's almost no battle at all, and then you reach the end with the totally evil leader just sitting in his knees, begging for mercy. Yeah, this man looks ruthless.
All in all, there's really no point getting this DLC. It's too easy. There's no notable loot. The story is boring. The characters are annoying. Just don't bother.