Yeah ABP kind of appeals to me. I'm not using it for two main reasons. First and foremost, I really wanted to see how Pathfinder plays with all the default rules. For now, I'm even tracking XP and encumbrance, which I wouldn't normally do. (Though I'm already thinking about ditching XP, at least for the low levels. In D&D I usually wanted to get through levels 1 and 2 and get up to 3 after 3–5 sessions at most, before slowing down after that.) I wanted to see how things go in vanilla and adapt when I see what is and is not working.
The second is Pathbuilder. It's an incredible tool and I've already bought it, as has at least one of my players. And at least one more player is seriously considering it. But the free version doesn't support ABP and I didn't want to force the players to purchase it to play.