Ranked in these QuestionsQuestion Ranking
Pro Heavily developped
Has active contributors, including Google and some quantum computing companies engineers.
Pro Type inference and type checking
Incorrect type declarations are treated as errors. SBCL can deduce types quite well.
Pro Actively maintained
Bug-fixes, performance improvements, refinements. New ports.
Pro Fast native code compiler
SBCL (and CMUCL)'s compiler, Python, produces optimized native code.
Pro Easy install
Portacle makes it easy to install SBCL, Emacs and SLIME.
Pro Free Open Source Software
Parts of SBCL are licensed under a BSD-Style license. The rest are in the public domain.