I realize that this post is 10 years old, but an update may be helpful.
Summary - I no longer take the Maglev FROM the Airport but try to always take it TO the airport.

I have traveled to Shanghai 6 times over the past 8 years (so knowledgeable but not an expert). I have found that the roads from the airport to the New Pudong district have improved a lot. And taking the train to then find a taxi (or subway) back from Longyang doesn't really save time and is usually be more of a hassle - long walk to the MagLev after a long flight, trying to get a taxi at the station is interesting, and the subway is a bit of a walk from the Maglev and then a long walk from the subway to my hotel. So I find it much easier and faster to just get a taxi and go straight from the airport to my hotel.

On the other hand, I take the train back to the airport every time now. The only time I didn't is when my last meeting was Tangzhen area and it would have taken longer to get to the station than the airport. IT is easy to have a taxi drop you off at Longyang station, buy a ticket, and relax on the train. There is a bit of a walk once you arrive to the airport, but the walk is nice before boarding a 10 hour flight.