I see many people say that Mongo is unfot for a production db, but it is actually used in production by many companies. Obviously this is true of many products

I see many people say that Mongo is unfot for a production db, but it is actually used in production by many companies. Obviously this is true of many products, but how serious is it in practice? The criteria for 'good enough' can't be passing Jespen because very few db's do. Storing schemaless json is a very valid use case. And the fact is there aren't really many proper NoSql alternatives, other than RethinkDB, which I hope becomes popular, and maybe Couch. e.g. Cassandra is often touted but its a k-v store, not a document db. There's a reason Mongo became and continues to be popular. I still think Rethink is superior in every way.