The primary purpose of the crown is to protect the muzzle end of the lands. That is why all crowns are recessed to one degree or another. The benefits of a recessed, concaved, etc. versus a straight flat muzzle is that it is protected more as to were the straight flat muzzle is much more susceptible to dings and/or nicks that will disrupt accuracy. As long as the crown is cut true and square to the bore, regardless of the style, is all you can wish for. As far as styles go, some will swear by their functionality, but to me they are cosmetic. I will cut any style a customer wants, but I will always make sure that whatever style it is, it is cut true and square.