I think Neovim is more flexible -- a plugin you write for neovim can run in the terminal, in any Neovim GUI or in another application (like VSCode) that can embed Neovim.
I tried to use Neovim several times. However, it appears to not be very friendly for my usecase, which is using it with a Braille display. A lot of Neovim UI elements only use background/foreground color to indicate highlighted positions, instead of making use of the cursor. I couldn't even use the intial plugin menu. Emacs is much better in thsi regard.
