SBCL, mostly on Linux, but also a bit on OSX. Both platforms work really well, but the experience is a bit smoother on Linux. On both platforms I have a scrip

SBCL, mostly on Linux, but also a bit on OSX. Both platforms work really well, but the experience is a bit smoother on Linux. On both platforms I have a script that pulls from Git, rebuilds, and installs over the previous SBCL binary image, so I'm using the absolute bleeding edge of the compiler. One day this will bite me somehow and then I'll start using the most recent stable tag, but it's worked okay up to now. I use Emacs and Slime for development. I had used Emacs for a long time before using CL, so using Slime wasn't an issue for me at all. I know the commercial implementations have some neat IDEs, but I haven't tried them. I'm not sure there's many (or any) OSS alternatives to Slime. On both platforms I use QuickLisp to install all of the Lisp packages I use. Pure Lisp libraries always work great on both platforms. Libraries that wrap C/C++ libraries (like Qt or SDL) tend to work better on Linux, but in every case I can think of I've got them working on OSX also, with varying degrees of effort. On Debian I "apt-get install ..." the required lib* and sometimes lib*-dev packages, and then (ql:quickload ...) has always just worked. External libraries on OSX are where I've encountered the most problems. Qt was particularly tricky, and I'm not even 100% sure what I did that finally got it working. SDL has some hoops to jump through with a "cocoa helper library" that I had to build by hand, but it's pretty simple and a few minutes Googling turned up enough info to get it working. For the majority of the stuff I've needed (libpng, cairo2, mpg123, and a few others), I was able to install them with HomeBrew, and they just worked once I had my PATH and LD_LIBRARY_PATH setup correctly. OSX ships ancient versions of several libraries (like libpng), but installing the version in HomeBrew usually fixes the problem.