Nolan Ra's best feat was physically besting Nolan Batman (which is not that great to begin with). But not only that, a Batman in a very bulky, cumbersome 1st film armour, IIRC. Now Ra's did display decent striking power, being able to still affect Batman through said suit, but Frank has dealt with repeated blows from Matt's reinforced gloves (and Matt hits hard enough that he has broken people's bones on multiple occasions, just ask on-duty Nurse Claire lol), been tazed multiple times (he only went down when the tranq started taking effect), had a hole drilled in his foot, kicked off a water tower and bounced back first off the edge of the roof, etc. and still kept on trucking. Plus, in dealing with Matt, he has handled a faster and more agile opponent than Batman, especially bulky suit Batman. I'm going with Frank here.