I know I'm a month late, but I JUST got around to downloading and playing Mothership Zeta.
I've been so busy IRL and I've been avoiding this thread just so I didn't see too many spoilers.
I must say I'm not horribly impressed with it. It's not a terrible DLC, I've just found myself bored playing it a few times.
My favorite part so far was unthawing the frozen people. and I was confused as hell when I unthawed the raiders and the ghoul reavers and they started fighting. I didn't realize I'd triggered it at first. lol
I'm looking for the last damn generator or w/e to blow up on the cargo bay and can't find the damn thing.