[tmtvl]

So weird seeing CL code without a bunch of (declare (type (integer 0) n))'s everywhere. That's the only thing which keeps me with CL instead of Scheme (I'm rather fond of syntax-rules, case-lambda, case sensitivity, and being able to do things like...

  (define range+ (make-range-merger +))
  (define (double-range range)
    (range+ range range))

, which I think is a little nicer than

  (setf (fdefinition range+)
    (make-range-merger #'+))

or having to precede range+ with funcall everywhere I want to use it).

[lispm]

Personally I find Common Lisp in some cases slightly uglier, but clearer.

  (define foo (make-foo))

What is it? A function or a non-function?

I prefer the Common Lisp version:

  (defvar *foo* (make-foo)
    "*foo* is the current input/output foo object.")

It's clear that DEFVAR usually defines a variable and not a function. Bonus: we can document the thing in a standard way.

For functions I would define a define macro.

  (define foo (make-foo)
    "foo is a function with two arguments of type bar, it returns ..."
    (ftype (function (bar bar) baz))

Which would expand into a (setf fdefinition), a type declaration and setting the documentation.

I prefer the uglier, but better standardized and slightly more practical language.