I'm really looking forward to see how much HTTP/2 will increase performance for my Bitcoin payment channel server: https://github.com/runeksvendsen/restful-payment-channel-ser...

Just now I finished separating the front-end and back-end - by a RESTful protocol - and this roughly halved performance compared to using a native library (from ~2000 payments/second on my laptop to ~1000). I expect HTTP/2 to make a greater percentage-wise difference here, although I admit I really have no idea how much, say, ZeroMQ would have reduced performance, compared to cutting it in half using HTTP/1.x.

I expect HTTP/2 to make a much greater difference in high performance applications, where overhead becomes more important, which static file serving doesn't really hit. So I think RESTful backend servers will see a much more noticeable performance increase, especially since, if you use Chrome at least, as an end-user you already get many of the HTTP/2 latency benefits through SPDY.