[medo-bear]

for me the following things stand out

use common lisp (sbcl) if you want c-level performance

use common lisp if you want to make optimizing compilers

use common lisp if you want smalltalk type repl driven interactive development

[rscho]

I'm not a compiler expert by any means, but I would've thought the more functional nature of racket to be a plus for writing compilers. Plus, there's the nanopass framework.

[lispm]

There is no shortage of Lisp compilers.

The new Racket compiler was derived from the Chez Scheme compiler.

[medo-bear]

ohh ... almost forgot ... CLOS

https://en.m.wikipedia.org/wiki/Common_Lisp_Object_System