I visited the Tanger outlets before going to the Premium Outlets in Chandler. The stores were pretty much the same, along with the sales. I would say there's really no point visiting both malls as there's really not that much difference, I would actually recommend going to the Chandler outlets as it is close to Arizona Mills which have Last Call by Neiman Marcus as well as Saks Fifth Ave off 5th (so you can do both malls in one shot).
However, if you are not in close vicinity of Chandler, then this outlet is "good enough" to look for deals.
On top of outlets, one should check out Desert Ridge Marketplace in Scottsdale as well.. we ended up buying more things there than all the outlets as there was a ROSS, Marshalls, and a DSW!