This Thor is more powerful and versatile over all but that magic resistance is a pretty good defense so Thor will have to use the power cosmic mainly.
And let's be honest, is an in character Thor going to even use the power cosmic? Like at all? He's probably going to brawl it out and Prime is to fast to lose that one. He has the power and options to easily beat Prime if he decides to use them though.
Thor w/bfr-9/10
Thor using all of his abilities with intelligence -7/10
Thor fighting in character-3/10