[RobertKerans]

React Rails[1] works fine: you just get React, and it's difficult to integrate other shiny React-associated stuff like Redux, but it makes it incredibly easy to build out an app, or even just sprinkle components throughout an existing Rails app. It's dead simple to get started, and I've found it generally Just Works; the whole team I work on has been using it for the last 4-5 months without any issues. Just add to Gemfile -> it sets up a components folder + a file that imports the file tree -> then optionally set initializer options (like include React Addons, or use stage-0 stuff). All exposed globals though, which is a pain, but that's generally expected with the asset pipeline unless you're very disciplined.

There's a pretty complete tutorial, but it's a bit out of date + uses CoffeeScript rather than JSX - I made a copy of the original, with updates, for one of my colleagues, the gist is here (sorry, might be a little rough): https://gist.github.com/DanCouper/b6953544a34606617eb5

To get a bit deeper, there's React on Rails[2], which retains the same entry point, but moves all the JS to a separate folder at root, and uses Node to handle that side of things during development. The setup is batteries included, and pretty flexible, but I haven't used it a huge amount so can't give much detailed feedback.

1. https://github.com/reactjs/react-rails

2. https://github.com/shakacode/react_on_rails