Of all APs ever, I'm going to say Age of Worms.
Of all the APs I've ran or played in that are Pathfinder, I'm going to say that its a tie between what I'm playing in (Kingmaker, we're about to hit book 6 with a really good DM.) and what I've ran (Rise of the Runelords).
I also really like Carrion Crown though as has been said, it feels like a guilty pleasure running it, especially because half of my group are former LARPers who know and love the associated horror tropes, from Cthulu to Dracula. The lethality of the AP is also appealing to them. My players loved playing Council of Thieves; I hated running it because of the ton extra work required to keep it coherent. I rather enjoyed Legacy of Fire, but that's because I ran wild with some of the themes of Lamashtu, Rovagug, Gnolls, Katapesh, and Denizens of Leng. Sometimes a little railroad is nice for a quick and easy to run AP, yet one where expanding upon anything there works really well. Sort of like how the Devil's Platter is detailed in Runelords; its world-building which is important to make a setting feel populated.