PVG attracts a lot of unscrupulous taxi drivers (scammers). You will see that there will be a disproportionate number of non-major brand taxis at PVG (red and dark blue ones). They won't rob you blind, but oftentimes the meters are rigged to run 5-10% over the correct amount. As a one-time tourist you probably won't (and shouldn't) care but I'm a crusader and have refused to pay sometimes. (I know the exact distance from PVG to my home).