I 100% agree with Yac, Point Lookout is indeed the best and that Chinese Spy quest was really cool and the background story to the quest I found very fascinating and I actually wanted to finish it to find out what happened next.
That quest is also worth it because of the reward you get.
Best quest ever.
Point Lookout is hard as **** though. The game designers cut a few corners and if you go in with a max level the enemies can do stupid stuff like ignore your DR and..GODDAMN those enemies wielding the double barrel! damn them straight to hell!!
Good news is you
can return from it
technically at any time, (for an exorbitant fee), but you nontheless
can return, which is in stark contrast to all other DLCs.