I was playing with https://github.com/reactjs/react-rails a couple of mounts ago.
There is a prepopulate method so I could render the initial page server side. I had seen other implementations for еmber as example.
Under the hood rails calls node.js by default as far as I remember.
Going this way was too tedious work for the project that I was working on so I scratched the idea.
As of now the prerendering is the only way I have seen if the SEO is a must for the website/application.