How does it compare (feature-wise, performance, stability) with e.g. hunchentoot (which clearly wins the naming contest)?

I think this runs only with Allegro Common Lisp, a commercial implementation.

Not really, you can run this under SBCL too.

I need another hint. The sources seem to depend on Allegro specifics, e.g. the :excl package (with the enlightening description "General extensions to Common Lisp").

Yes, AllegroServe is Allegro specific, but there is Portable AllegroServe: http://portableaserve.sourceforge.net/

It's the same situation as OpenSSH. OpenSSH only runs on OpenBSD, and Portable OpenSSH is maintained separately.

Five message into the comments and the discussion devolves into compatibility issues between various versions of common lisp.

Welcome to CL hell.