if you mean strength as in AP, both jon and michael are 9-B via scaling from skull-crushing feats. if you mean strength as in LS, jon probably has the advantage there, too, since he should scale to class 1. endurance would actually be one of the easiest things for jon to get around, since he can take quite a beating himself and he has experience fighting entire hordes of wights, whose endurance should be just as good as michael's, if not better. as i said earlier, michael doesn't have any experience against someone like jon, while jon has a season 8-load of experience against something like michael.