I have been looking at Win32 solutions to the same question. As far free Lisp implementations on Windows, I would strongly recommend Clozure CL (CCL). There are several reasons for this. The first is that Clozure supports 32- and 64-bit binaries. It's very fast, and somewhat compact. But most importantly, it's consistent and correct. I find it to be an extremely mature Lisp, after working with Lispworks (which I miss) for several years. CCL does a very nice job with native OS threads, sockets, and some other elements that are not part of the CL spec. Its implementation of CLOS seems to be extremely thorough. And it's GC and memory management are excellent. I compared CCL to SBCL on Win32, and while SBCL was a bit faster on several benchmarks, it cons'd up a lot more, and its image kept growing and growing, even after several forced GCs. Meanwhile, CCL was consistent, small, quick, and lovely to use. And if you want a platform that's consistent across Windows, Mac, and Linux, and has both 32- and 64-bit support, then look no further.
I did try CormanLisp on Win32, and there were many things about it I liked. But it does not run properly on 64-bit Windows platforms, and is limited to Win32. It's also not free, and somehow I had it crash on me when I'd throw some garbage code at it. I also was easily able to make SBCL crash. Not so with CCL. Rock-solid. Really, those guys did an amazing job, and ultimately will help keep Lisp alive.
As for SLIME, I didn't try to get SLIME working with SBCL, but I did get it working nicely with CCL. No matter what your fancy is, I advise that people write code to be easily portable. Aim for Windows, Mac, and Linux, and aim for 64-bit. If you consider these, then CCL is your best choice overall.
A last attempt at an answer to this is to consider what is wrong with the others. Here's what I've come to find:
- CLISP is nice, but is far slower, relative to SBCL or CCL. I see little upside
- SBCL seems poor on Win32. Image size can get big.
- CormanLisp is good on Win32, but not portable, and does not support Windows x64.
It also seems that Roger Corman is not actively developing CormanLisp, which is
a shame, but it's the reality.
- Clojure (with a "j") is not Common Lisp. As nice as it may be, I think that
if you already know CL, then it's not worth the overhead of learning Clojure's
many differences. I'm sure some may pick them up fast, but I surely did not.
(If Java-compatible code is what you're after, then look at ABCL).
dave