Very fast. Fast enough for on-the-fly minification in CGI scripts.
Installed and used this minifier with Perl 5.8.7 and 5.8.8 on Win32, Linux, and Solaris. All was good under Linux and Solaris. Win32 (VC6) was a challenge because make kept throwing errors about missing strings.h.
I found a strings.h under ...\cygwin\...\mingw32\include, and copied it to my ...\VC98\include\ but now the error was about not finding some functions;
So, after a longish session with a variety of Google search results, I found if I add a (macro?) block like this near the top of strings.h (as the second define block), it built successfully on Win32: