The performance of Compojure was really impressive, which was almost three times as fast as play-scala. I was expecting the opposite, considering that Scala is generally a bit faster than Clojure.
From what little I know about Play, it does a lot more than Compojure does. Compojure is really just a routing library. This is a benchmark of Ring (HTTP communication), Compojure (routing), Korma (database access/abstraction) and Cheshire (JSON serialization). I'm pretty sure a basic request in Play goes through more middleware than that.
But yes, the performance of a reasonable web app stack on Clojure is very good.
But yes, the performance of a reasonable web app stack on Clojure is very good.