Not nearly as good as volume 1. 
 1) Vol 1 has 5 issues and Vol 2 has 3 issues. Yes, vol 2 also has Thor Annual #1 and What if? #10, but they are kind of lame. 
 2) Thor is not nearly as bad ass as she is in Vol 1. In Vol 1 she kills frost giants, in Vol 2 she gets her ass handed to her by a metal robot. 
 However, there is still a lot going for Who Holds the Hammer. 
 1) We find out who the goddess of thunder really is! 
 2) We learn about Dario Agger's past. He is a pretty bad ass villain. I'm definitely a fan. 
 3) We get shirtless Thor, but a lot less, and the artwork is a little more cartoony. He is still sexy though! 
 All in all, a solid 3 stars. I would only recommend if you liked Vol 1. I sincerely hope Vol 3 becomes better. Not that Vol 2 is bad, but I just want Thor to be oh so good! Kick ass female superheroes for the win!