I spoke with a "grizzled old Lisp hacker" at my Clojure meetup here in Minneapolis. He let it drop that "If I didn't know the problem in advance, I would choose Racket over any other language. I love Clojure, though. I just don't get as much opportunity to use it." There's room for everyone here.

Here we go again with the "any Lisp that isn't Clojure isn't practical" argument. I disagree. Guile and Racket are plenty practical, and both have dynamic FFIs to any C library you want so I couldn't care less about using Java and its terrible VM boot time and build systems. I'm not interested in "good enough" when I've already been using something better for years.

I'm a Clojure developer and I agree that people shouldn't use the argument that other Lisps aren't practical (I'm just happy people are using lisp based languages). The point we should make is that for any shop that's using the JVM or Javascript already it's easy to introduce Clojure/ClojureScript into that environment without a ton of risk.

Curious if you could tell us more about what you've worked on with Guile/Racket in a production environment?

I'm not the persuasive person that convince the bosses to use Scheme, so I don't have a triumphant success story, but some minor victories. I'm one of the core developers of GNU Guix (a package manager, distro, and associated set of tools) that recently was deployed successfully in a large production HPC cluster in Germany, which I think is a pretty nice achievement. At work, I use Guix and an init system called DMD (also written in Guile) a lot for development, and I'm trying to slowly work them into production via Docker.

It's an uphill battle to advocate for something that isn't the status quo, so I'm proud of the little victories.

If you build systems that are part of an existing ecosystem, specifically an ecosystem built on Java technologies, then Guile or Racket would be terrible choices.

Sure, that's fair, and for that Clojure is a fine choice.