I prefer Janet, but Fennel is great in places Lua is already supported, like in Löve2D.

https://git.sr.ht/~benthor/absolutely-minimal-love2d-fennel

One thing I've found that's really nice with Fennel + Love2D is you can even do hot reloading with nvim+conjure[0](I assume emacs too). I assume there's a way to hot refresh with just straight Lua but it feels very natural to do with a lisp.

0(example config): https://github.com/TheBlob42/love2d-fennel-neovim