This is super helpful to know and corresponds well with my experience when trying to learn Blender. As I had not followed along all those battles of the past, I miss a lot of context. That makes it hard to judge what is considered best practice now and what is the idiomatic way to do things.
What would you recommend? Is it worth getting used to right click select or is left click select OK? Are the new 'default' hotkeys good or is there an advantage in being able to use the old key bindings?
First, not all veterans stay with the old ones. Second, going forward all learning material and documentation will use the new ones. Third, even those veterans who stay with the old shortcuts for convenience mostly don't see it as a war and will tell you to just go with the "new" flow.
And last, but very much not least: it's a numbers' game. There are quite few veterans (Blender was and still is relatively niche), but a boatload of new Blenderers learning it right now (or having started within the last three years when the UI revamp was released). And many many more than even that boatload of new people will start learning in the next few years.
What would you recommend? Is it worth getting used to right click select or is left click select OK? Are the new 'default' hotkeys good or is there an advantage in being able to use the old key bindings?