i played the new vegas dlc old world blues. it's kinda strange, i enjoyed playing it, but i'm not terribly inclined to give it a particularly glowing review. it's got some neat ideas and has some rather funny/well executed scenarios, but like puppet master suggested, it's really fallout-centric, almost annoyingly so.
i wouldn't say that the overall presentation of it all was that effective either. the story was interesting and resolved itself in a satisfying way, but the pacing and juxtaposition of it all was jarring to the point of being ineffective. it's almost like two separate storylines in one, the absurd science backstory and the grim reality of what their experiments have created. don't get me wrong, i don't fundamentally have a problem with either one of those, and think both are reasonably well done for what they are, i just felt like those two storylines didn't help each other out very much, and were contradictory to the point where it damaged their effect. you couldn't laugh as much at the scientists because they are SUBSTANDARD DISGUSTING LIFEFORMS and you couldn't feel as strongly about the experiments gone wrong because LOL ONE OF THE SCIENTISTS IS FLESH/APPENDAGE FETISHIST. not to say that neither work, because i think both do, i just think there's sufficient separation between the two that the momentum the various elements of the story are creating lose a lot of positive effect.
also, i found the humor of it really hit and miss. sometimes it felt forced and not terribly inventive, and other times i thought it was really spot-on and clever. it's strange how this would change almost from line-to-line too. one moment i'd be actually laughing out loud and the next i'd be shaking my head. they get a pass here though because it was often funny and game writers have proven themselves otherwise incapable of doing this.
one thing i found kinda frustrating/stupid is that they go out of their way in the dlc to give you the ultimate BASE for storing your shit and selling/making items, but by the time you get to this in the game you're already really settled into other places like the lucky 38 or novac. and you're really going to need to be leveled into the 30s or 40s at least to even make much of a dent into the dlc given the absurd difficulty spike, meaning you're really not going to get much use out of this anyway since you'll already be near the end of the game. i went out of my way to transfer all the thousands of pounds of shit from the lucky 38 to the new base you get in old world blues and felt PROFOUNDLY SILLY for doing so. just a poor design choice. i understand the use of making something like that in the game, but placing it in a location that you'll really only be hitting late in the game is just dumb.
kinda rambled too much about this, but it's only worth picking up the dlc if you're really a fallout enthusiast and really dig what you've seen in new vegas. but if that's the case you probably didn't need me to even suggest it to you. who am i even talking to here?!? i am talking to nobody!!! i am speaking to a dialtone!!! aaaaaaaaaaaaaaaaaaaa