I've been using Hy on and off. Off because it broke "let" at one point and I had a few critical things (like my entire site engine) written in it, and on because I like it a lot. But it's not a great LISP for performance (Fennel can run rings around it when using luajit), and I wish they shipped a 1.0 (I cringe every time I read the changelog for a release and check the "breaking changes" part, which is always... beefy).