Note that I’m primarily a Java dev so this is an external point of view, other with better experience/insight should probably answer here, but: I’d say this is a matter of preference… 
NodeJS is neither a language nor a framework, but rather a platform built to execute Javascript code on the server side.
It has web frameworks of course, a lot of it! So you have to find the one you want to use, start learning it, etc… Comparing frameworks and distinguishing which ones will have the best community support, the longest lifetime and shortest learning curve can be tricky… With node you’ll start this journey from scratch (but it’ll be a flexible journey).
Also Javascript may be easy to learn at first (arguably) but has a lot of quirks and surprises. It is on the weaker side of the “strongly typed vs weakly typed” curve, so you can easily make mistakes without the compiler explicitly showing you where you did.
Ruby is a dynamic language that is considered elegant and very productive by its user base. It has a stronger type system and therefore may be more adapted to you, depending on your taste.
Ruby on Rails is the de-facto standard web framework there AFAIK, so the community is large and there’s less dispersion into hundreds of framework. The framework is opinionated, meaning it assumes you’ll build things “the Rails way”, but that can guide you and gives you great speed of development.
As I said, matter of level and preference, I’ll let Node and Ruby devs chime in 