There's a difference between using an MVC pattern (which is easy with Express, but is completely optional) and relying on an ORM (which the project forces on you). One of the great things about minimilist frameworks like Express is that you can build it out and customize it like you need.
The types of projects that benefit from being in node.js instead of Rails, Django, etc, don't really benefit from having all those decisions made in advance. If the "Rails Way" works for your project, you'll probably benefit from doing it in rails. There's certainly more library support and it's easier to find more experienced developers for Rails than node.js.
There's a tendency to put all kinds of projects in node now, just because it's "hot". Some projects benefit from node, and some would be easier to do in some other language/framework. If you're experienced with Rails and are working on a project that fits that style, you're probably better off just doing it in Rails rather than switching to node and using a Rails flavored framework.