Thanks for mentioning JSPM/System.js. It's really cool; it runs ES6 compilation with Babel (or Traceur) in the browser, and is able to download arbitrary versio

Thanks for mentioning JSPM/System.js. It's really cool; it runs ES6 compilation with Babel (or Traceur) in the browser, and is able to download arbitrary versions of dependencies off a CDN. I'm still fiddling a bit with hotloading React and caching source files, but it looks promising.