I haven't played them all (or even most, or even three...) but I've been involved in many "best AP threads" and the one thing I've taken from those discussions is that there really isn't a "best." There are some people who have read all or many and played in many, and can talk about how the writing is, and the adventure design, and the linearity, etc... But what these threads always come down to is that they're literally ALL good campaigns. Some are written better than others but NONE of them are perfect and ALL of them have faults in the story/writing here and there depending on your outlook.
This being the case, the main thing to consider when trying to choose one is the material itself. You wanna pirate? You wanna giants? You wanna horror? Well the pirate one is good, the giant one is good, and the horror one is good. Even if the pirate one has better writing and overall adventure design than the horror one, if your group doesn't dig pirates then you probably won't notice how much "better" it is because you won't like it at all anyway. It's just not like there's two horror APs, and the two can be compared. Paizo generally has high quality adventure design, so pick what you like.
As such, I didn't vote!