[PhrosTT]

I'm using React + Redux + Koa (+postgresql). The most annoying thing with JavaScript right now is that Babel gives you all ES6 features in your front end bundle, but node 4 only has a subset, so you have to remember when you to stop using features. (No I don't want to transpile back end code).

[odiroot]

It's not really a problem now.

I use the auto-transpilation trick with Babel. You can see a small example in my repo: https://github.com/odiroot/songs-to-spotify/blob/master/src/...

Then in required modules you're free to use ES2015.

[desuvader]

You can use Babel with node on the back end. See https://babeljs.io/docs/usage/require/. Definitely not the most ideal solution, but it allows you to easily transition into ES6 when all the features land in node.