Like I said in a different reply, it was previously possible to compare right on Debian's language shootout page. Apparently they took out that feature, so here's an old link to somebody comparing SBCL, Factor, V8, and LuaJIT.

http://factor-language.blogspot.com/2010/05/comparing-factor...

All four languages have improved over the last 8 years, but you can see SBCL and LuaJIT are in the same ball park, each winning on some tests. My recollection is that SBCL usually "wins" in the number heavy tests like Mandelbrot, but I don't have time to dig up the links.