Real talk, Mass Effect 3 DLC Citadel may very well be the absolute best piece of anything Mass Effect related. You get a mission that's got more real fun meat to it than anything but possibly Shadow Broker and then you get a hecka fun combat arena simulator full of endorsements, crazy fans and competition as well as an arcade and some real fun moments with your crew (Zaeed losing his shit playing a claw machine, RIP Robin Sachs). The best part of the mission has your entire crew (plus Wrex) all fighting at the same time, everyone trying to one up everyone else. But the mission isn't even the best part of the DLC, the party afterwards and real final crew interaction is. It's good stuff.
If Mass Effect 3 was more of this and less of everything that wasn't Rannoch or Tuchanka, it could have been one of the most memorable ends to a series ever. The villain is like the anti-Kai Leng. They're actually hateable for a good reason and not for being complete shit.
TLDR: Citadel is better than all Mass Effect DLC combined (save for Shadow Broker or Overlord...but it's better than either of those on it's own).
I should have posted this in the ME3 thread.