DPS Improvement with the expensive weapon enchants over Shattered Hands.
Probably class specific, but - is there theorycrafting, simcraft results - or anectodical evidence - available on the DPS improvement you can get with the 15-crystal weapon enchants over Mark of the Shattered Hand? In general, or for specific specs.
I read somewhere (Collision's fury guide that's stickied in the Warrior forum here, I believe) that Shattered Hand recently got nerfed. Something to do with its PPM. Which apparently was enough to make Thunderlord superior, at least for fury warriors. That all being said, I haven't done any testing/math myself. I usually just go by what players like Collision say/do.
Doesn't matter to me though. I don't have the greatest weapons yet and won't be dropping that much gold for 2x Thunderlord on what I have. One 630 weapon and one 645 weapon that has less than optimal stats are not worth that much gold to me.
You can do this in simcraft, just load up your character and switch out the enchants manually. I would advice you to do that or ask on a class and spec specific basis whether Shattered Hand is better than 15 crystal enchants or not.
For example I'm a 651 ilvl sub rogue and for me shattered hand still beats mark of frostwolf by ~480 dps in my simulations.