On the basis of what we have seen, none, but he hasn't had much of an opportunity. He had two outstanding seasons at Malaga. And many keepers come good around his age.
Perhaps it is not right to say he's a top keeper with a reputation like Joe hart, Courtois, Cech etc, but he's still a very good keeper and he deserves a bit of respect. Done well for us. Understandably a bit shaky at times but then he must always feel under a lot of pressure when he plays. I can think of some fringe players who have really struggled when they've played the odd game.