Right now testing and giving feedback is still a bit too brittle, since too many moving parts are involved: my asm.js demos here (
http://floooh.github.io/oryol/) and here (
http://floooh.github.io/oryol-samples/), are all ready for wasm, and sometimes I'm putting wasm builds up there next to asm.js and PNaCl, but it's hard to automate the build like for asm.js and PNaCl. At the moment there's are bleeding edge build of Spidermonkey, binaryen and emscripten required to work together. Depending on the current phase of the moon this works or doesn't work (e.g. right now I'm having compile problems of Spidermonkey on MacOS 10.12 beta with the Xcode 8 command line tools).
I'm sort of holding back at the moment until emscripten has everything integrated to build wasm binaries, even if it is not the final LLVM backend. But I can't wait to flip the switch on the wasm builds :)