Personaly i found abcl a bad experience.
Thoughts on ecl & clisp ?
sbcl works nice & fine. But i’t’s the only lisp implementation i know.
There are good books on racket-scheme & chez-cheme.
The only book i know for lisp is, “Common lisp , a gentle introduction to symbolic computing”.
CMUCL is basically a worse version of SBCL. SBCL is a fork of CMUCL with the goal of being more maintainable. Some things have been backported between the two, and there maybe a few things present in CMUCL that aren’t in SBCL, but I think most of the interesting things have been added back in.
Clasp is to C++ like what ABCL is to Java. I haven’t done much more that fire it up to see if it would run, but it’s C++ integration looks fantastic.
CMUCL is also way behind it platform support. CMUCL is mostly limited to being a 32bit application (IIRC). SBCL OTOH supports various 64bit platforms, incl. ARM64 on Linux and macOS.