I've been crunching some simple numbers trying to find out which stat I want to stack to get the most DPS for my Gunner specc'd Commando. I found something very interesting, I don't want AIM at all when compared to crit. As it turns out, on an ability that does 1000 damage 1 crit rating will cause me to do roughly 17 more damage, where as 1 aim will cause me to do 3.6 more damage. Essientially 1 crit = 4 aim. I assume this works for all other primary stats as well. Which in turn makes customizable gear terrible, and crafted artifact gear where you can get upwards to 80 crit rating much more valuable. It seems wierd to me that the high level vendor gear gives so little crit in comparison to crafted gear.