Pre-Lisp-Machine IDEs were already more advanced. See for example BBN/Xerox' Interlisp mid 70s. Generally Lisp still offers a lot, but if you don't know what t

Pre-Lisp-Machine IDEs were already more advanced. See for example BBN/Xerox' Interlisp mid 70s. Generally Lisp still offers a lot, but if you don't know what to look for, you might not see it even if it is before your eyes. Even though the Clojure community reimplemented much of SLIME. It also might not be important to you. Stuff like having a Lisp compiler written in Lisp, having an actual interpreter, being able to dump images, low startup times by default, break loops, readable stacktraces, type checking compilers, resumable error handling, embedding in C applications, whole-program compilers, compilers which can create C code, ...