Lisp-Stat is conceptually similar to R and will be familiar to most people from that ecosystem. It is suitable for both exploratory data analysis as well as front-line production deployments. Common Lisp is currently used at Google in several high-availability, high-volume transactional systems.
Why Lisp?
We had a few requirements when evaluating options. Specifically the system had to:
Work well in the kind of exploratory environment conducive to analytics and AI
Be robust enough to work in an enterprise production environment
Be available under a license without source code restrictions
Common Lisp was the only framework that met all these requirements.
Probably the most important reasons though are given in the paper by Ross Ihaka, one of the originators of the R language, Lisp as a Base for a Statistical Computing System about the deficiencies in R and the inability to compile to machine code (among other issues). The same is true of Python. In that paper he argues for Lisp as a replacement for R.