I can also answer that as I've a fair bit of Rails experience. This time, we built our API using nodejs/expressjs for the first time, so we had to learn it plus the ins and outs of handling user login, sessions, CORS and a lot of small things Rails does for you. So we wouls probably have been faster with Rails.

If we need to build another product from scratch again though, we'll definitely be faster with nodejs. I understand that nodejs programming seems strange/hard to do in a non-spagetthi way to some people, but really, after a few months it is not hard.