Wow, I'm surprised that there is not a single post in here yet. Let's this to be the first one. I'm using NeoVIM tbh but we all know where we came from, right ?
Async, so a few things don't block. If you have a plugging manager that updates, you can work while it does its thing. Clipboard is set up by default.
The big thing was the code itself was refractored so more than just Bram can work on it.
Having language server support built in ir nice, and using lua as a plugin/configuration language is pretty nice (but I haven't looked at the new vim9 script stuff)