I've talked about him before in this thread.
Im a Porto fan, watch every game.
He is gonna be 31 in couple of days, at best he will be a good sub. He is not United material, at least not the good old United.
He is very intelligent player, a massive diver(although he has toned that down a bit lately), great penalty taker, good passer, good with the ball, good pressing, problem is he is a bit slow and his finishing is inconsistent. He is capable of amazing goals(bicycle kick against Chelsea in the CL for instance) and missing easy sitters.
His stats look good but he scores penalties, he scored 7 last season.
Most Porto fans will be happy if you take him, we need the money and he is barely good enough for Porto, that's the truth.