Short, fun, and very good looking expansion.
The story starts you off getting a job from a caravan company to venture on a trading trip to a place called New Caanan in Utah, and you will be going through to be stopping in the southern National Park, Zion. When you get there, you are ambushed by tribal raiders called the White Legs, and your caravan company is gunned down, you being the only survivor. You meet an scout from another tribe who wants you to meet a man named Joshua Graham, aka the famous burned man from FO:NV.
Now, for the stuff I liked.
Zion is a cool environment, with nice looking visuals, and a good amount of differing terrain, and places to explore. The story, although linear, has you explore and do the regular grind, but then things get very fun at the end, and I was very happy to get a change of pace. The sidequests are different, but rarely challenging, and rarely that interesting. You get 2 tribal companions that will help you for a while, and you also get ol' Josh as a companion for a while, and it is pretty awesome that they finally have some companions in an expansion for fallout. (I did not play Dead Money, mind you.) I also enjoyed the new weapons, (especially the Survivalists Rifle) which felt balanced and, although a slim variety, quite fresh.
Now for the bad stuff :(
However, Zion, unlike Vegas, feels a bit unrealistic. Having been to Zion multiple times, I was saddened to see that there wasn't really any real locations from the park, unlike the Vegas area, which had real places like Primm to explore. Another thing is, the environments feel a little empty of cool places, ranger huts, campgrounds, and lookout points are really the only buildings you are going to find here. Unfortunately, the Mormon characters are as obnoxious as their real life counterparts, and constantly throw religious jargon at you that you don't care to hear. Most of the main story line is fetch quests that have you getting lunchboxes to help tribals and such. It also feels empty of people you can actually talk to, as there is less than 10 friggin people you can actually talk to up close in the game. The last thing is it is SHORT. 4 hours approx. for the whole game including sidequests, and although you may return after you finish the story line, all of those less than 10 talk able characters are GONE. So it is empty and there is little reason to return there after the story is over.
Overall:
It is barely worth the 10 bucks, but having been there a lot, I bought it without a thought, and was a little dissapointed, however, if you are really interested in the Burned Man, or want to do some more exploring, or just are bored of New Vegas, this is a decent buy. If not, look somewhere else for your kicks.