Well, as I stated: in Smalltalk I can trace statement by statement (compound statements work flawlessly), make a change to a method and the debugger does the right thing. With SBCL under SLIME on Emacs I have to fiddle around with optimize statements over and over, recompile mutliple times before debugging does anything at all, at which point it still doesn't work very well. Randomly skipping over sexpressions, etc., etc. The experience is awful and every time I've ask on #lisp I've been called an idiot for trying to debug instead of tracing (not even exaggerating, sadly).