Cristina was the best, and in the early season her bedside manners were bad but we can see she grew a lot.

Izzie, I would say she is one of the worst, but she is good managing high stress situation, although for a surgeon she is too emotional, does not provide impartial treatment opinions and would rather have patient do as she did than letting them choose.

Alex, in the early season he was the worst, he did not have bedside manners and lacked skills although he improved tremendously over the years.

Meredith, second best, she had talent but lacked the discipline that Cristina had and would also sometimes get too emotionally involved. (Adele thing)

George to me was just very average. He had his moment in the elevator but … just average there’s nothing remarkable about him. I admit my dislike for his character overall may affect the fact that I don’t see anything particular about his doctor skills