All of them give the shuttle. The codes also give you 2 days of play time for free, but you can only get time once from each of the four. So having 2 "A" codes doesn't get you any extra time, but having 1 "A" and 1 "B" code does. And it looks like having all four gets you an extra 2 days, for a total of 10 days of free time. And you can use the time even if you haven't purchased the game.