Article's author seems very favorable of Node: which would be lower on my list the Rails as a server-side language.

I believe Rails is still a great option in case you want to use an existing team and where strong performance is not a requirement. Learning Rails is currently a very minor bump in the road, since (1) the language is easy to pick up, and (2) the framework is well documented (every possible question is on stack-ex it seems).

For now I'd look in the direction of Go, Erlang/Elixir, Clojure and Haskell as the new contenders for doing web development. They all have their own strong points, and I personally resonate most with Haskell (strong typed, manageable maintenance curve a.k.a. happy refactoring, fast enough).

So why not Node? It's because of JS. The language is the biggest "API" you will ever write against. Moving away from it is called either a rewrite or a port. So making a choice for a language should be made carefully. And design choices when making a language should be made carefully. In case of JS the design was clearly haphazardly done: and this will leak into any code written on top of it.