At this point MySQL is playing catch-up to MariaDB.
MySQL was first in offering JSON with 5.7. It is still well ahead, for example, there is no JSON_TABLE, aggregate functions, native type or partial update in MariaDB. Some examples of the value here: https://mysqlserverteam.com/mysql-8-0-from-sql-tables-to-jso...
Both have always had GIS support, but have taken it in a different direction. With MySQL, the GIS is now based on Boost.Geometry and has Geography support.
w.r.t. metadata in transactions - I am not sure which feature you refer to here. The native innodb-based dictionary is a MySQL only feature.
For Window functions and CTEs, they were added at a similar time, but MySQL is on a ~3yr release cycle. MariaDB is on a ~1yr.
The same complaint that every single person brings up about MySQL when being compared to Postgres, including in this thread: DDL changes made during transactions cannot be rolled back.
Source: have code that works on both.
I think Mariadb was there first. I think the format is very similar at the bit level, but the MySQL has nicer API with automatic returning it as text to apps rather than exposing the bits. I dislike json_extract and wish >> worked but it doesn't seem to on my percona server :(
Anyhow, you'll look back when you've got more distance from Oracle and realize that you don't need to try and convince yourself that MySQL was better quite so hard ;)
I wish we could be more civil and not resort to petty insults. Is there anything I wrote you can dispute with a source?
* The JSON datatype guarantees the content is valid JSON
* access to fields can be faster even without dynamic/virtual columns
* since 8.0 there are special optimizations for doing partial updates, which means that not the full JSON data has to be rewritten on small changes https://mysqlserverteam.com/partial-update-of-json-values/