It's quality and making rapid progress.

I've been using (GNU) emacs on and off for, uh, 30+ years. And it's close enough that it mostly feels right. But many things my fingers and eyes are used to are different enough to be jarring that I'd have to re-learn some things.

Still, I just fired it up and started editing Rust code and -- unlike GNU Emacs -- it came with a pretty much working LSP auto completion setup out of the box. It's not RustRover level fantastic, but it's good enough to do work. And a lot just works out of the box that has to be configured and set up manually for GNU Emacs. E.g. it comes with a project explorer like Emacs projectile, already all set up.

I just wish I could make it bring up the M-x line on the bottom like GNU emacs, instead of in the middle of the screen?

EDIT: nevermind, found it:

  (setf lem-core::*default-prompt-gravity* :bottom-display)
  (setf lem/prompt-window::*prompt-completion-window-gravity* :horizontally-above-window)
  (setf lem/prompt-window::*fill-width* t)