As a Liverpool supporter, you have no idea how much I loved every moment seeing Maguire's confused face look when he does a blunder. But as a neutral supporter watching him play for England at the last World Cup was actually very nice!
I actually don't mind Maguire for United or England. Granted he is not the best technician or speediest defender out there but he reads the game quite well and he will get all the air duels in the match. It is up to the manager/coach to organize the defense to suit him. You have to push opposition players to the flanks and then he will make good work of all those crosses. If you leave him one on one with fast players he is doomed