I have a 531 equipped iLevel Elemental Shaman, Wusholays and Breath with LMG.
I reforge Mastery > Haste. I gem 320 Mastery in Yellow, 80 Int 160 Mastery in Red. --- My SimDPS on LightMovement is 190K DPS @ 25000 Iterations.
I reforge Haste > Mastery. I gem 320 Haste in Yellow, 80 Int 160 Haste in Red. --- My SimDPS on LightMovement is 193K DPS @ 25000 Iterations.
Despite my scale factors for the heavy mastery build telling me Haste is my best stat, the heavy Mastery build only does ~3K DPS less than the pure Haste build in single target. However, the heavy Mastery build is godly for cleaving and the DPS from Chain Lightning spam is just wow. I'd ignore Totemspot for stat weights and go full out Mastery, you'll be doing less damage on single target fights but more on anything that allows you to cast Chain Lightning. The DPS difference (at least in my case) is so small, I'd take the added AOE bonus anyday.
http://eu.battle.net/wow/en/characte...tesia/advanced