I've been a lisp hacker for decades, and always code/test from inside emacs using shells. (Emacs+CL is pretty much my OS!) I've never really found SLIME to be much more useful than basic emacs. This, however, looks like it might attract me to actually moving a little bit away from raw emacs. The mains reason that I tend to use raw emacs is that I hop around multiple servers quite a lot, and I find it annoying to have to carry around my emacs environment, and when servers get reloaded, all my personalization gets wiped, so I've learned to make the most of the raw emacs env. This thing seems to provide enough additional machinery that it might be worth dragging around.
