It's not just RoR vs Node.js, it's the eco-system around it you need to think about. This is an interesting read as far as Node goes: <a href="http://www.breck-mckye.com/blog/2014/12/the-state-of-javascript-in-2015/" rel="nofollow">http://www.breck-mckye.com/blog/2014/12/the-state-of-javascr...</a>
Use <a href="https://www.meteor.com" rel="nofollow">https://www.meteor.com</a> . You want to build prototypes as fast as possible, and meteor enables you to build stuff shockingly fast. RoR is a thing of the past.