The Famo.us session (along with a couple others) at last year's HTML5 conference in SF is what made me decide to make the shift to full time iOS development. Every benchmark was presented in terms relative to native app development: "transitions are 95% as smooth as native apps;" "rendering times take only 3% longer than native apps."

Of course mobile web development is important, but I don't really see where Famo.us's market is. Full feature desktop web?