Alright, so I just picked up the 503 caster dagger from elite protectors, and was chatting with another ele who I'm friends with about gearing. He's recently switched to mastery gearing, and he ranks consistently with it. So I went ahead and simmed my gear and, sure enough, mastery comes out ahead.
The thing is, I'm currently using Primal Elementalist with my haste build. I find it to be very forgiving rotationally, and since mastery doesn't affect either of the elementals, haste is a no-brainer. With mastery, I would be using Elemental Blast. I used EB initially when I hit 90, so I do know how to weave it in my rotation, but it's never a particularly clean affair. You're bound to lose out on some damage due to human error in spell selection.
So I went ahead and did a DPS check with lust, flask, 300 int food, and pre-potting, running around 7 minute fight (3 ascendance and 2 eles) on the training dummy. With the haste build and PE, I did about 77k over the course of the fight. With the mastery build and EB, I did about 80k over the course of the fight. What I'm really curious about is whether that 3k is going to be worth it (or even existant) in a real-time fight. It seems like the drop in mobility due to EB might actually be a hindrance, especially on higher movement fights. But I also know I'm throwing away free damage periodically when I get haste capped by any two haste buffs being active at once (sha trinket, hero, etc., though this is less of an issue now that I've upgraded to jade spirit instead of windsong).
What is everyone else doing? Thoughts? Suggestions?
Armory/logs if needed: