That's tough. I'd go Edwards not because he's been the best by any means (and some of his performances have been poor) but its been a step up and he's grasped it with both hands. He's the only one I don't think we could have asked more of considering it is a step up.
Some games he's been poor however his stats are good, he's scored some goals and generally played well enough. Sub par is harsh for me. Stoke have been sub par though for sure. Allen so far,Ince that's about it. Eric has been goodish