What sites do you use for stats?

Let’s face it, League development, design, and debate is data-driven. Anybody who wants to discuss how balance and design should be done is tapped into stats sites, but...which one is the best? What should we take as the gold standard for debate?

With op.gg’s inability to separate stats for regions and trouble catching up to patches versus champ.gg’s notorious wonkiness on some metrics and the obvious discrepancies between them, which of these sites do you use? Why do you use them? How do you explain their various quirks? Do you have any alternatives that you think are superior and want to crow to the world about? Let us all know.