I see more of Luna than River Tam in Folly, mostly because the Etherealists aren't actually insane, they just seem that way to people incapable of interacting directly with the Ether. Yes, they have their "holes", but none of them have behaved erratically (yes, I'm including Ms. Cavendish, she's sadistic and evil, but very predictable). You never knew when River would go off, I don't get the same vibe from Folly.