“For an end-user without much deeper knowledge, the biggest differences might be XDG_PATH based directory and init.vim file name.”
For years the honest pitch for Neovim was a different config path. Version 0.5 finally changes that with a built-in language server client, Lua and Treesitter. The fork also pushed Vim itself to ship async jobs. Competition did more for Vim than a decade of mailing list arguments.