Not bad, but pretty skippable
The first DLC out of the gate, and looking back it's pretty obvious. After a quick bit of footslogging to find the actual quest line, you do some good ol'd mutie-killing before the real, actual content: a "simulation" (read: FPS game pastiche/homage) of the war in Anchorage against the Chinese. Success brings a great perk: the contents of a O:A-era storeroom full of items "acquired" during the war.
This wasn't the best DLC, by far. The problem with it, personally, is it's a one-shot; if I miss something in the simulation once I get to the Outcast base, it's missed. Thankfully, only one beneficial thing can be missed like this (Covert Ops perk), but it still feels like a silly thing to not let you re-do the actual SIMULATION. Still, the schwag's pretty immense, so it might be worth it just for that. I mean, permanent Stealth Boy when in Sneak Mode? Awesome. The quest itself is a quite forgettable experience, but a quite funny "homage" to the "realistic" shooter action of the COD/MOH style games, with some interesting insights into the history of the world. Not bad.
Achievements-wise: not hard at all. Just find and finish the simulation.