I recall he was big into SBCL, but most IT organizations wanted all code to run on the JVM or CLR. So he had to make a Lisp to run on the JVM and Armed Bear Common Lisp apparently wasn't exactly what he wanted.

I want to learn Clojure, but there are definitely some road blocks. I don't have the time for Emacs, it'd be a pain to get a Cursive license (although the cost is extremely reasonable I'd have to do paperwork at work), and I don't know the JVM or Java well.