I've used both, or rather, tried using both - lsp-mode never quite worked for me, whereas eglot is rather simple in comparison and easy to set up. lsp-mode doe

I've used both, or rather, tried using both - lsp-mode never quite worked for me, whereas eglot is rather simple in comparison and easy to set up. lsp-mode does 'more' (and there's also an auxiliary package, dap-mode, for debugging), but I guess is somewhat more brittle because of this. dap-mode I do use, by the way (for python mainly) - functionality-wise it's my favourite debugger available in Emacs. eglot further has a single developer who already assigns copyright to the FSF (and developed other packages, like flymake, which are already part of emacs), so it has that going for it as well.