Seriously, is there a reason you have to hint about what Lisp you use?
If you are interested, I'm using LispWorks <http://www.lispworks.com>. The other large commercial Common Lisp implementation is Allegro CL <https://franz.com/products/allegro-common-lisp/>.
If you are interested, I'm using LispWorks <http://www.lispworks.com>. The other large commercial Common Lisp implementation is Allegro CL <https://franz.com/products/allegro-common-lisp/>.