Are you aware of any memory-leak issues with fset? I once used it in a game where I updated an fset sequence in real-time. I let it run for a while, after coming back I noticed my computer was completely frozen (out of RAM).
Just personal preference and enjoy programming in it. Programmers give too much importance to programming languages.
Clojure can be made to run very fast (it compiles to the same bytecode as Java after all) for the hot paths at the cost at writing less idiomatic Clojure.