Personally I think both guys are pretty awful and are only relevant because of the severe lack of talent/depth in the heavyweight division. Either Lewis swings wildly early and stops Volkov or it goes to a boring decision with gassed fighters and Volkov edges a decision.
Volkov has actual talent and technical abilities. Lewis has brute strength, good power average technique But with horrific cardio. He can definitely catch Volkov.. But if Volkov can keep him at kicking range it's going to be an easy nights work.
I always pick against Lewis, the guy is trash. Where he is at in the present is just a testament to how crappy the HW division is. Volkov should put him away inside the distance.