I thought that given Steven Tyler doesn't sing all that well to begin with, at least to my ears, I thought he did a pretty decent job, he really could have gone all crazy like he does with his songs, but he tried to sing it pretty straight - IMO. But then again when I heard it announced that he was singing, my expectations were pretty low.
I thought he would have better range.
I agree. His voice was never sweet music to begin with, and factor in his age his performance exceed my expectations.