I think Charlotte is underserved with only three malls, but of all three, Northlake is probably the best bet for mid-level retailers in a decent setting South Park is out of my league and Carolina Place seems more and more crowded these days. Turning off 485 and immediately having to turn into the mall parking lot is a nightmare on busy weekends, as well as navigating the crowded corridors.
North Lake mirrors Carolina Place in that it offers the same retail chains or their equivalents. No big secrets here, just run-of-the-mill mall clothers and none of the high-end hoopla of South Park. Sadly, it seems that Carolina Place has absorbed the remaining low-end clothing retailers that left Eastland last year. The other major difference lies in the fact that Northlake has a cinema, Fossil, and a Borders, while Carolina Place has a Barnes and Noble and JC Penney. I still think the Northlake is the best bet because there is a Target nearby (might as well lump all the shopping venues together) and some nicer restaurants (notably PF Chang and Firebrids).
P.S. Don't waste your time at Starbucks! The cafe in Borders is far better.