Well, I've been using Node.JS in production for over two years, now. However, here is my experience:

• + I love love love working with ES6. There are so many JS tools which make debugging and monitoring a bliss
• + Modules for lots of things which make it a piece of cake to patch an application together
• + Lot's of freedom separate software for application, caching and serving cannot deliver
• + Super easy to write, version and replicate an application
• + Zero down-time is possible
• + Drop-and-run bundles: no complex installations and dependencies
• - The garbage collector might ruin your day, when it starts collecting a gigabyte of data at 9AM (might only be in my head, since the particular problem was already fixed in Node.JS)

Best takeaways:

• Asynchronous functions (with async/ await).
• ES6 syntax.

Worst takeaways:

• Use of too many (simple) dependencies (haneycodes.net/npm-left-pad-have-we-forgotten-how…).
• Lack of ES6 modules.