Im not meaning to sound disparaging to United with my comments by the way, there's some players there I think are world class or genuinely top class ( RVP, Rooney, Hernandez, DDG) but I think SAF made some players appear better than they were in the same way that Jose has made some of our decent and or average players look a lot better. Because of this you have a false sense of the overall quality of the team, as the quality of players is often variable depending on the manager.
You can bleat on about having a good defence on paper still but there are 11 teams with a goals conceded rate better than United and you cant put all of that down to the midfield or the rest of the team, its all excuses if Smalling, Evra, Jones, Evans Vidic and Rio were still the players they were/are supposed to be that would not be the case. ( make no mistake I rated Vidic as the best defender in Europe in the past.)
Nani has looked ok in periods but he has not done anything great and is behind what City, Arsenal and Chelsea have to offer, Valencia has looked good in places too, but again nothing amazing. United major strength is in the striking department where RVP/Rooney.Hernandez are only slightly behind Citys offering, and way ahead of the rest, and the GK is top class too, best in the league is arguable, its very close between him Mignolet Sczeny and Cech imo, all have strengths and weaknesses.