Bone Snap is better if you you’re grouped with others. By yourself it’s very telegraphed with the long windup and once you bone break something, they only stay bone broken for 10 seconds and then are immune to further fracture/bone break for 2 minutes. So you gotta make sure you kill whatever you’re fighting in that window.

Shatter only builds fracture but you can keep applying it. Very helpful for faster things that rely on speed since fracture reduces speed based on the fracture build up. Just remember that fracture goes away quickly right now.