Some advice please: which OS should I build for, to have the easiest experience kicking the tires? OS X or Ubuntu 14.04?

I still really enjoy Common Lisp (even though it seems like I spend my time with Clojure or Haskell) and Clasp, when it is mature, will be a good incentive to use Common Lisp for more development use cases. (It is easy enough to build stand alone executables with SBCL, CCL, and Franz, but having a smaller executable would be really good, if indeed the executables would be smaller with Clasp).