Slightly off-topic, but I have worked with another tool by the author (Jepsen), which is also written in Clojure and in fact a Clojure library. I'm fairly proficient with functional programming in general, but had never touched Clojure before. My experience working with Jepsen was quite frustrating simply because of the fact that it's a Clojure library. Clojure is dynamically typed and it happened fairly frequently that I had to dig into Jepsen's source code simply because some type errors were only caught very deep in the call stack. Jepsen itself is a really great tool and I'm a very big fan of it's creator (Kyle Kingsbury), but the fact that you can only use it through Clojure is kind of sad. I guess it gets better with more clojure experience, but a dynamically typed functional programming language is kind of too much of design flaw for me to want to invest more time in the language.