Let me get this straight - Dead Money is definitely aimed at the more hardcore Fallout fan, as there are quite a few new mechanics in play here that make this DLC incredibly tough, and for me at least, incredibly frustrating to play. Firstly: around the Sierra Madre complex, there are clouds of poisonous gas that sap your HP. At times, you have no choice to go through these clouds. Next: there are radios and speakers scattered around the environment that will set off that collar around your neck should you stay in their vicinity for too long. Some of them can be destroyed, others are shielded and either have to be avoided or shut down via terminals if this is possible. There are also strange and creepy "ghost people" roaming the streets that will hunt you down and kill you. Knocking them down won't deal with them permanently, you have to dismember them with a spear or other sharp weapon. What's more, all of your equipment is taken away from you by your captor when you first arrive and supplies are in incredibly short supply.
Now I dare say many fans of the series will actually relish the challenge on offer here, but I found it really frustrating and after a while, not at all fun. I guess I like my open ended RPG experiences which let you explore - which most of the time the Fallout games are - but when they force you into a certain situation like this DLC does and The Pitt for Fallout 3 also did (but not quite so extreme), I can't honestly say I'm a fan. So, the score I'm giving out here is purely based on my opinion and how much I enjoyed (or didn't, actually) this DLC. If you played the main game on Hardcore mode, or like challenging gameplay, then give it a shot.
Overall: 5 out of 10