>>> I have to admit raising an eyebrow when I saw that web page. In that report, MongoDB lost data and violated causal by default. Somehow that became "among the strongest data consistency, correctness, and safety guarantees of any database available today"! <<<
It's not wrong, just misleading. Seems overblown given that most practitioners know how to read this kind of marketing speak.
So basically whatever MongoDB was doing 10 years ago, they are continuing to do there. They did not change at all, yesterday or two days ago there were few people defending mongo that indeed in early years mongo want the greatest, but it is now and people should just stop being hang up in the past.
The reason why people lost their trust with mongo wasn't technical, it was this.
Based on this, my understanding is: most of the time you want a relational database. If a relational database becomes a bottleneck for certain data, and you don't want to do typical scaling solutions for relational data, then you need to know what you'll trade for the higher performance. Based on what you trade, you then decide what kind of data store you will use.