I'm somewhat frequently exposed to absolute beginners and MEAN does occasionally pop up as one of the various flavours of "I picked a thing before learning the language, now what?".
Other popular contenders are similar "full stack" or "full featured" solutions like Sails, Meteor and Total.js.
This is generally a result of beginners to Node trying to find something that does everything instead of spending some time learning the basics with a library like Express and going on from there.