To be honest, my experience with Lisp is limited. The view I had of Lisp being slow was due to
Working with a platform that was implemented in Lisp by pg that was slow and memory intensive compared to other languages.
A discussion between Paul Graham and Trevor Blackwell where they benchmarked some simple and common operations using C, Perl and Lisp.
(I'm trying to dig it up now.) If I remember correctly, ANSI Clisp had to perform around 400+ operations to print a single character. Don't quote me on that though. I'll try and find the doc.