<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by gnaget:
On UA you have this long walk to the mobile lounge and then they wait until everyone, including the FAs, get on board. That can easily take 20+ minutes after arrival.</font>
This is not my experience. The mobile lounges arrive and depart on a set schedule. They dock and then leave no more than 10 minutes (and I think it's less than that) later regardless of who's onboard.
I've not arrived at IAD from an international destination so I can't comment on any difference in the process.