The loop/recur syntax gives you recursion in constant stack space.[0] It was a bit of a speed bump coming from Scheme but it's just part of being on the JVM. Personally, I'm more than happy to take some ugly TCO syntax if it comes with the all the good stuff Clojure inherits from Java.

[0] - http://clojure.org/special_forms#Special%20Forms--%28recur%2...