Well, what I was mainly refering to was the fact that the servers were fucked for like three days, though, you are right on it's high-occurance of lagging, connection losses, and several other irritating-software bugs. Oh, and there are a lot of douchebags who use it daily. See: MWS Horror Stories thread for more info.
However, despite it's difficulties, it is still probably the best software for Vintage online play.