[clartaq]

I think of the "Lisp A vs. Lisp B" discussions like describing the nuances of you favorite color. My favorite color is yellow, but that covers a lot of ground. I prefer a nice bright lemon yellow, but don't care for mustard yellow or brown as much. But any Lisp is better than Fortran just as I prefer any yellow over purple, for example.

I prefer Scheme to most other Lisps because of guaranteed TCO, the way continuations are handled, regularity of function names, and define-syntax macros.

Within the Scheme family, I usually prefer Chez for its performance, its FFI and because I happen to prefer an R6RS compliant system at the moment.

Just nuances.