I have access to the same information as you, so unfortunately, I don’t know.

The article literally says you will still be able to push books via Calibre etc, but won’t be able to download books into Kindle from PC.

Example: If you don’t have a WiFi at home, there is an option to connect Kindle via USB to your ethernet connected PC and download books from Amazon that way.

And this option is going away, as most people have WiFi.

Anywho, fuck Amazon (for other things, but not this one).

The answer is impossible to answer until you tell us more about your needs. Better choice considering what?

In general, untill you have terabytes of data or a significant amount of traffic (operations per second) database choice does not matter and you should be using cheaper option, where the cost should be assessed as a derivative of price of hosting, cost per operation, cost to deliver (how familiar you are with it).

When you have significant amount of data or traffic - only then you should worry about database kind or language. Until then this could be a premature optimization.