A lot of the i180 gear is mostly better than fully melded i150 gear. By "mostly better" I mean it has a significant boost to one stat, a small reduction of another, and is a wash with the third. Getting the full set will see stat increases overall, but not if you only look at individual pieces.
The i180 accessories, however (belt, earring, rings, bracelet, neck) are hands down worse than the other stuff. That's why we crafted the i170 for those slots. We would have crafted i170 for the i180 pieces, too, but there are (or were) no i170 crafting recipes for gathering body, legs, hands, head, and feet slots.
Now, the i190 is easily better than the old stuff. The only reason I'm doing anything for the i200 is my retainers. I am not sure whether or not to make i170 accessories for them however.
