Just to relate my own experience with a Simon Outlet (Arizona Mills) and Outlets at Anthem
http://www.outletsanthem.com/ north of Phoenix, I found good deals on clothing and shoes. At one time Anthem had a Reebok outlet where I could get 3 pair for the price of two (as long as one pair was priced less than the other two) and they were Reebok quality. I could buy three pairs of shoes for work for ~$60.00 and get shoes for nine months and year after year they had the same shoes. With my job at the time, I could wear golf shirts and jeans, and could get good prices on Greg Norman shirts, and Reebok shirts, usually $10.00 to $20.00. With Arizona Mills they had a JC Penney outlet where I could get golf shirts for $8.00 to $15.00 just after summer. All of these were usually first run clothes sent to the outlet after the winter clothes came in to the regular stores.
I could get between the two and a trip to Target for Wrangler Jeans, a years worth of work clothes and shoes for ~$250.00.
Arizona Mills has gone through changes of stores, they had JC Penney, Virgin Mega Store, Macy's, and they now have Needless Markup, Nordstrom, Sak's, and others, but it has maintained since the mid 90's, and hasn't become a vacant waste land.
The one in north Phoenix, still does quite well, and the two have enough different stores that they don't compete directly. Are there stores that are not real discounts? Yes, don't go to the Bose store and expect a bargin. Does Arizona Mills have a Ross and a Burlington Coat Factory? Yes it does, and I can tell you that I won't buy from Ross/TJ Maxx/Marshalls.
Both outlet malls in Phoenix have been in business for close to 20 years, and don't show any decay, dying, becoming a waste land of vacant places. The original Tanger in Stroud was a good idea, but as been mentioned, who wants to drive 50 miles to save less than what was spent in gas and tolls getting there, and really, who wanted to stop and shop there on a road trip.