One good aspect about some European airports is that they have a good rail connection to the city. Here in Denver, there is a rail, but it only goes a few hundred meters, adding an unnecessary delay, especially during off peak hours.

Another good thing about Schiphol is the blackjack tables (which even Las Vegas airport does not have).

Any survey which can pinpoint airport to #1, #2, etc. is flawed in my opinion. Its better to give grades A, B, ...