Before I got my current chestpiece off Zul'Jin, I was using the season 3 chest. Also, since the Isle was first introduced I've been using the 18 stam 20 resilience head glyph from SSO rep. My defense right now is 478, and the 20 resil makes up .5% crit reduction. If I still used the s3 chest, I would have more room, like 450 defense if needed. You just need to find your happy medium, you might for instance gem your PvP chest with dodge/def gems due to the already high stamina. Again I reiterate it is all up to preference.
"There are no men like me...only me."