Just got back from PVG today. In fact I'm typing this at the DTW Skyclub as I wait for my conneting flight to NYC. Was there about 9 days on an DL Award ticket. I agree with Bennos when it comes to shopping, not cheap compare to come other cities. But I absolutely loved the food. Maybe it's because I opted for chinese cuisine rather than western cusine while I was there? As for things to do, I'm sure there are plenty as well.
My November open-jaw ticket into Beijing 11/6 and out of Shanghai 11/14 is also an award ticket open to change depends on what extra activities people are interested in.