Having hacked a decent amount of Clojure, I've learned that Clojure can be very fast or very slow depending on which features of the language one chooses to tak

Having hacked a decent amount of Clojure, I've learned that Clojure can be very fast or very slow depending on which features of the language one chooses to take advantage of. A perusal of the Clojure Google group will illustrate many examples where a few small changes to a program give an order of magnitude performance boost (or penalty for that matter). This makes it somewhat difficult to write performant code in Clojure (for me at least) as a lot of experimentation is required. Additionally, a given program has to run for at least a little while before hotspot JVM optimizations kick in which make a huge difference.