Also the sheer amount of stuff they print. They are continuously putting out high quality adventures with a storyline that makes sense and doesn't have giant blank spots that you're expected to fill in for a few levels. They're switching to a quarterly hardcover model instead of a monthly adventure next year. The rulebooks are nice and paizo isn't shy about making new ancestries, classes, and options for existing ones, and they balance the more odd or possibly unbalanced options by making them uncommon or rare such that they require GM approval to take. And a whole bunch of setting books that examine all corners of their world, from over views of whole continents to deep dives into specific cities.