He doesn't need to impress for us. He only needed to be available. It's hard to compare our GKs with others because of how we play. When you have 60% possession each game, you may only be required four or six times a game. As long as you're solid in those slim situations, you're good. I think he's good, but he's not world-renowned.
From what I've seen at Man U, I would say they have a similar level keeper.