While the rules of Age of Sigmar might be up for debate about their merit, the sculpting capabilities of Games Workshop really aren't up for debate. They've really gone all-out for this one, I have to say. You can now order Archaon Everchosen over in their webshop.
Maybe it's just me, but I think a massive, winged, 3-headed, and 2-tailed monstrosity is pretty damn cool. And I know it's supposed to have the rider on there, but if I were to get one, I'd probably leave him off. Or at least, I'd magnetize him so he could be either off or on as I saw fit. I'm sure my D&D players would face against it, possibly as often as it'd see the wargaming table.
Along with the Archaon, there's a bunch of bundles available to order. But let's face it, we're here for the big monster.