I have been committed to NodeJS, Express and the MEAN stack for a few years now. It has made my life as a developer more efficient, especially when integrating with various cloud services -- there's a node module for everything! But the real game changer has been an ExpressJS / React based application framework called KeystoneJS.
Yes, KeystoneJS is just an Express application, but it's a really good one! Its backend admin interface is a thing of beauty, very elegant and minimal. It gets you from defining data models to a workable interface in minutes.
The design pattern is ExpressJS all the way, and that gives me comfort that I don't have a lot of custom backend code that can't be reasonably understood and maintained. It also means that KeystoneJS is rock solid. Combined with PM2 and MongoDB.com, it just keeps on going even under load.
If you are looking to get into NodeJS or ExpressJS, KeystoneJS is a very solid choice. I highly recommend using Beta 4, and don't let the beta label fool you, it is very solid.