Well, for priest and warrior, T4 isnt very good. Cant really comment on the other classes. The odd thing about the warrior T4 leggings and shoulder is that your hp will drop but you gain more strength and agility when replace the Kara drops. As for priest, with T4 my mana regen went down substantially and +healing only slightly up, which I thought was louzy. The warrior 2 set bonus is very good though. I noticed a big improvement in dmg mitigation. The priest set bonus is horrible. It buffs the group heal, which just gets you killed in places like SSC and The Eye.
I think for some classes the crafted gear is better. My priest has his T4 leggings and shoulders in the bank. Use the mooncloth set. Zul'Aman has better gear. Then again, I think ZA is probably more on par with SSC in terms of difficulty.
I think for some classes the crafted gear is better. My priest has his T4 leggings and shoulders in the bank. Use the mooncloth set. Zul'Aman has better gear. Then again, I think ZA is probably more on par with SSC in terms of difficulty.