Povetkin all day. He would bust Andy up and stop him. Better boxer, better power, better defense. Better legs. Andy has a slight edge in hand speed.
Povetkin is the better fighter overall, but I do think Ruiz's hand speed will give Povetkin issues. But Ruiz is just too easy to hit and that will be the difference. Maybe Ruiz makes it to the final bell but I expect to see him get dropped at least once.