How does it differ from uBlock (or, how is it better?)

It's maintained by the original author. The readme is a good place to start researching, but it's not that interesting a topic tbh.

https://github.com/gorhill/uBlock/blob/master/README.md

I read this and the wiki page and still have no idea which I should run (usually Chrome / Mac if that matters). I'm using non-Origin right now.

Sorry, I thought they linked to this https://github.com/gorhill/uBlock/wiki/Maintainership-transf...

Note: that's an old version. The current revision is here https://github.com/gorhill/uBlock/wiki/Maintainership-transf...

It doesn't seem to matter which fork you use, but I personally use uBlock Origin

So the original author transferred ownership (incl. github page) to a the uBlock community, in reality to one of them. It turned out he handed it over to s kid who in turn made some weird source code changes and asked prominently for money/donations.

This scheme seems to popular with adblockers, afaik the original AdBlock and the AdBlockPlus had a similar "relationship". And later a German company took over AdBlockPlus in a similar manner and is doing big business in a gray area (whitelisting domains costs ad networks a lot of money and is absurd for an adblocker!?)