To be fair, Node.js isn't exactly harder to work with than Django or Rails. I myself had to choose between these about a year ago and despite the asynchronous paradigm I still found it relatively easy to start using in comparison to Rails and Django.
Node.js is extremely hard to work with compared to Rails and moderately hard to work with compared to Django.
The Node.js ecosystem has a lot of potential, but the variety of off-the-shelf add-ons is severely limited compared to either of those more mature frameworks.
If you think Node.js is easy, you've never really experimented enough to understand what makes Rails so effortless. It's a lot easier to produce a production-ready application with Rails than it is with Node.js as it is today.
In four years, as Rails starts to add less critical features, Node.js may well have caught up.
I used to think this until I built an app with node... every time I got to a point where I wanted a library or framework, a mature, well-supported one existed. Yes I had a bit of a learning curve since it was my first node app, but I was shocked at how smoothly it went and this was over a year ago.
When you want a 100% solution and Node gives you a 95% one that 5% can be a deal-breaker. Node is nearly there, which is frustrating because it has so much potential, but it's just not yet.
I think in the long run Node will beat the pants off of Rails but it's going to take an enormous amount of work to make that happen.
Sinatra is a lot closer to Node and Django than Rails in terms of philosophy. It's more minimalist, where you must assemble a lot of your environment rather than be issued one by default.
The missing 5% is mostly things that make your development process more effortless.
I've found that it's easy to get a first cut of an application out inside of two weeks with Rails, but you will probably need more time or lower expectations when working with something more limited like Django or Sinatra.
Since Rails imposes a lot of conventions, applications are easier to organize if you follow the rules. Sinatra is far more open to interpretation, so if you're not disciplined it can turn in to a bit of a mess.
I'm a big fan of the DRY principle and it's much easier to apply within Rails than in other environments. A lot of this relates to how Ruby is a lot easier to meta-program than other languages.
Coming from Rails, Node is like opening a toolbox and finding it has a screwdriver, a wrench, and a hammer. Somehow you're expected to build things with that.
For those that love to build things from the ground up or to carve out new solutions, Node is a great place to be. I think it's got enormous potential and is biggest opportunity since Python and Ruby took off around years ago.
Just don't think because you can create the same sorts of apps with Node that it's as easy.
Ruby on Rails even three years ago was laughable compared to today's toolset. Node is catching up quickly, covering ground faster than Ruby ever did, but still lagging.
