HDL

Straight from a Blue, without any of the EJ idiocy and rampant speculation:

http://forums.worldofwarcraft.com/thread.html?topicId=16473618356&sid=1&pageNo=4#77

All the numbers and formulas are making my eyes spin.  It seems though that for PVE its still pretty much useless

Stack it until your eyes bleed. OK, not that simple, but it should be a non-trivial boost to damage. If you also check Ulduar gear, you'll see a lot of ArP.

Bottom line, take it and love it for your melee hitters.

Just FYI, it's not very good for Ret. The majority of ret damage is holy so ArP does nothing for it. But for warriors and rogues and I think even DKs it's supposed to be pretty nice.

Yeah, Rogues, Warriors, Blood DKs are all mostly physical damage, so they benefit the most.  Frost and Unholy DKs not so much since they have a lot of magic damage as well.

Ret paladins shouldn't dismiss ArP though. Three of the Retardin's abilities are still physical damage, white swings, crusader strike, and divine storm.

Someone asked how much this really boosts your damage. I was going to build a spreadsheet and cut and paste, then found Wowwiki already had a nice chart!

This assumes white damage of 1000 per strike and a level 83 boss. Yes, it scales more against armored mobs than unarmored. That is by design to prevent light ArP stacking crushing clothies.