yeah, I'd say 90 to early 2000's I think after the invincibles it started to wane a bit (Arsenal kind of became media darlings because they were so pretty on the eye, like current City). I think as United became more efficient and Ferguson drifted away from 442 it wasn't as much. Of course the Tevez, Rooney, Ronaldo team too but that was drooled over on merit.
Your team that beat Mancini's City never got the credit it deserved imho. That City team was probably the most balanced and strongest team we've ever had (till this season). One of my big issues with Pelligrini was the way he disassembled that team and gradually made it weaker. For me that was one of Ferguson's best titles, because he beat a truly top City squad with a very average United one. Don't think there is another manager in football that could have done that. As you say that team got far less credit than deserved, even if they did look workmanlike.