Items CAN have different stats, but basically all items are the same statwise. Ie; they all have a stat pool that can be a myriad of different things, so that you can specialize in one stat or another, but once your in the top tier items, they all have the same amount of total stats/damage.
All gear is absolutely even in Spvp.
The same goes for pve/wvw. While there is a top tier you can reach, after that, anything 'better' is based purely on cosmetic and what works for your particular build, nothing is inherently more power than anything of the same tier.
I think it goes like
Normal - white
Fine - blue
Masterwork - green
Epic - yellow
Legendary - gold