After famo.us' initial hype and about 2 years in beta. I expected something cool. Maybe a UI kit built with great 3d effects, like a 3d version of flat UI.
What I see is pretty disappointing.
Try stress testing any of their apps. The performance you get is insane. That is the killer feature.
I think those are quite amazing. Make for example size by size comparisation with Famo.us Yahoo weather and original Yahoo Weather. You can't achieve that kind of smoothness with traditional html rendering.
Those demos might not be that cool when viewing with laptop browser but when you test those with eg. iPhone you understand the difference.