Back in the day, I used to keep a log of airport travel times (taxi v. bus v. Maglev-taxi v. Maglev subway). On average, I found the straight taxi option to be the fastest, though the Maglev options were superior when I happened to catch a train within 5 minutes of showing up at the station (on either end). But, as long as the Maglev only runs 2 or 3 times per hour, the average wait times of 10 or 15 minutes put it at a disadvantage to the taxi (assuming a taxi queue of less than 5 minutes). Certain busses also fare surprisingly well in this contest, provided your hotel/apartment is close to one of their terminal points.

From my place in Shanghai (near the Portman), average travel times are as follows:

Taxi: 45 minutes
Taxi--> bus: 55 minutes
Taxi--> subway --> Maglev: 50 minutes
Taxi --> Maglev: 55 minutes

When I lived in Lujiazui (i.e. near the GH), the numbers were similar.