Ignoring all the other distinctions between lisps, the main difference between lisp-1 and lisp-2 (or lisp-n) is going to be how clean your code looks when you lean into the FP style. In a lisp-2 you'll need to do something like this:

  (defun apply-twice (f x)
    (funcall f (funcall f x)))

  (apply-twice #'1+ 2)

Versus this with a lisp-1:

  (define (apply-twice f x)
    (f (f x))

  (apply-twice 1+ 2) ;; assuming 1+ is defined

But there are so many other differences between the lisps in the two categories that this probably won't be the deciding factor for most people.