As much of a "bad wrap" that PHP has - you can still build a modern, functional app with it. You might not be able to move as quickly as with say Node these days - but it can be built. Although, knowing Rails, Php, Node, and a few others very well - I would spend the few weeks to teach the team node. The productivity saved down the road would be immense (I say this from having started a few tech startups 1php, 2rails, 1node)
You know, it's a personal choice and feeling. I know Ruby well, (bc I knew Perl very well) - but Rails 3 is just bulky and cumbersome. I felt like for the most part that I was wading through thick water every time we had to add more features. Granted, the Rails way I haven't agreed with, and we hated having to move from JS <--> Ruby/Rails or do the front end work in a clunky HAML/ERB view (we moved to using no views - just JSON API calls and rendering client side). We eventually found that the front end was JS & the back end ended up having to be python (for computationally heavy tasks). SO Rails just acted as the intermediary, which I felt was clunky. (Although I miss migrations in Sails JS). Does that help?
It's not magic per se. I will caveat that I never liked the way Rails does MVC, so I've always used Rails as logic source (api and SaaS "brain"). I abhor Rails View approach, as it's kludgey and requires a Rails team to make front end changes. But having a common language (js) works for me. And scaling Rails while is much more work (and I think requires a bigger team) than with Sails JS (which I use). Development seems faster (no measurements - just a feeling). Granted Sails built ins make the difference on moving faster in node.