Often when I read articles like this I take them with a grain of salt. A lot of hate for MEAN technologies seems to stem from people who don't know how to properly use them. You're not supposed to use MongoDB like *SQL and if you try you're gonna have a bad time.
Let's say I have a big pick-up truck I use to haul xWidgets. My friend gets a little motorized scooter to drive around town hauling his yWidgets. Is it proper for me to believe that my friends scooter sucks because it doesn't haul xWidgets like my truck? I don't know much about scooters, but by friend says it doesn't have a steering wheel and it only has two wheels. How the heck can it steer without a wheel? He says it has "handle bars" for steering. Seems kind of dumb but I guess it works for him. He touts the fact that he gets 80mpg on gas but it doesn't matter how efficient it is if he can't haul xWidgets. Scooters suck because they don't work the way my truck does.
Okay. What does this have to do with MongoDB, though? People in this thread have presented plenty of usecases for it, but every single one of them (pretty much--someone correct me if I'm wrong) is also satisfied by jsonb in Postgres 9.4, which in your analogy would make it a truck that gets 85mpg.
Let's say I have a big pick-up truck I use to haul xWidgets. My friend gets a little motorized scooter to drive around town hauling his yWidgets. Is it proper for me to believe that my friends scooter sucks because it doesn't haul xWidgets like my truck? I don't know much about scooters, but by friend says it doesn't have a steering wheel and it only has two wheels. How the heck can it steer without a wheel? He says it has "handle bars" for steering. Seems kind of dumb but I guess it works for him. He touts the fact that he gets 80mpg on gas but it doesn't matter how efficient it is if he can't haul xWidgets. Scooters suck because they don't work the way my truck does.