Whats better for arms?

https://www.wowhead.com/item=45498/l...amned#comments

or

https://www.wowhead.com/item=45533/d...avity#comments

?

I want to buy 1st cuz arp.

I'd say first as well because of the armor pen. The more you can get, the more valuable the stat becomes; till the cap of course.