That's largely accurate, but the core point that I try to convey is that Mongo's key sales pitch is that you get sharding and scalability, but at the cost of features like ACID transactions, foreign keys, consistency checks, etc. Today, we have a great number of options that don't have to make these pyrrhic trade offs, and are just as scalable as Mongo.

If you want something that's portable, pretty scalable, and fast, go with Postgres. If you need something that's really scalable, there are plenty of other good databases on that list.