I don't agree. To take a microscopic view of just one of them, consider TIMESTAMP. It was identical to DATETIME, except that if you touch that row, the _first_ TIMESTAMP column gets automagically updated to the current time. This isn't the kind of thing that happens by accident, someone decided that this was desirable and went out of their way to write code to make it happen. The feature caused a great deal of confusion and probably a significant amount of data loss. It's more than merely non-standard or in some sense "less" than Postgres, it's actually inimical to the model of what's going on, in several senses: column "ordering," a data type with behavior. This kind of "here's a bucket of special-cases" sloppiness is thematic for both MySQL and Mongo.
