[superuser2]

This is definitely motivation to learn another framework besides Rails and Django.

Compojure's syntax and design seem really attractive... is anyone using that in production? Would it be a reasonable choice for a "serious" web application?

[Zak]

I've used it for client work that was in production and for a side-project that's in production, but private with few users. It has been reliable for me.

Note that Compojure is more of a routing library than a framework. It's similar to Flask or Sinatra. Clojure's philosophy includes aggressive separation of concerns such that full-stack frameworks aren't really "the Clojure way".