For those of us who are good at doing it, we can blitz through it in about 2 hours, but it seems to take most groups 3-4 hours to complete.
I'm sure you can look at the statistics and see this is about the average amount of time. After which either you get a group of good players, or a group that has a couple of mopheads, which literally cannot for the life of them kill the queen.
I understand the need to having challenging content, but seriously... The huge amount of time invested into this does NOT balance into the rewards received.
There are several very challenging elements, which is good. But the problem is they're all stacked upon each other into one mission. That mission could have been easily divided into 4 separate episodes and we all would have been really happy about it. You instead made a marathon of it and by the time you get to the end (the hardest part) your men are tired and ready to go to bed.
Yes you can find groups that are at the same "stage" in the quest as you, but now that the cure is out.. those folks who haven't finished Infected (a pre-requisite for the cure by the way) it is really difficult to get them "flagged" to continue, because all the competent players have already completed infected and have no desire to do it again.