[jasondc]

This article from 8 years ago highlights how far MongoDB has come: transactions, left outer joins ($lookup), etc.

[nickkell]

How many years before it reaches feature parity with a traditional RDBMS though? And when will it get a query language as good as SQL?

That said, I will admit the change streams feature is amazing. That completely changed the way I thought about building reactive applications

[ashtonkem]

The issue is that MongoDB isn't chasing a fixed target. RDBMS have gotten better in the mean time.