I'm going with Povetkin. He looked very unimpressive in his last effort, but I think that was largely his opponents work, or lack thereof.
Good answer. Minto has twice as many fights as Povetkin. Maybe later down the line Povetkin could possibly win though. Right now Povetkin gets outworked and beat up by Mighty Minto who is entering his prime now.
While I agree that Povetkin would and ought to be the heavy favorite, I believe that this fight would be pretty enjoyable to watch while it lasted.