There is a minor annoyance that I haven't seen any of you mention. Sometimes when a debugger or compilation notes buffer pops up the first key pressed generates a 'buffer is readonly' message. From the second keypress on everything works fine.
This is with a very recent slime and emacs 21.3 from Debian Sarge.
Oh, and one more thing. I was trying to get slime work with a non-unicode aware sbcl and iso-8859-2 encoded files. I figured that setting (setq slime-net-coding-system 'binary) was the way to go. Unfortunately, when compiling a simple thing like:
(defparameter *xxx* "sdffdséfdsdf")
that contains a non ascii char slime hangs and gets disconnected if I press C-g. SBCL runs on and it possible to reconnect. This is the message from *inferior-lisp*:
;; Connection to Emacs lost. ;; [junk in string "emacs-"]
Cheers, Gábor