Fatal flaw: Versus mode (PvP) with random strangers is almost always awful. Only well-balanced teams of roughly equal skill can have a good time, which is unlikely when playing with randos.
As opposed to the co-op campaigns where it’s OK if some players are better than others because we’re all on the same team and a good player can carry several n00bs.
I haven’t been having any major problems except for occasional framerate stuttering, but then I don’t use that many mods.
My only real complaint is that there’s really no new story content, it’s just a couple of new locations (Enclave checkpoints like FO3) some new armor and weapon types, and a handful of quests that are pretty much radiant quests with a coat of Enclave paint. Considering the download was like 10GB I was expecting more. If Google is telling me the truth, that’s bigger than all the other DLC combined.
In New Vegas, completing Arcade Gannon’s companion sidequest gives you a suit of Enclave advanced power armor, and a squad of Enclave troops with a vertibird will back you up at Hoover Dam. It’s virtually impossible to trigger this quest by accident.