I don't have any preference. My version does depend on the presence of the syslog module, and I don't know how commonly-installed that is. But I don't know under what systems the debugging to stderr is supposed to work. Is that a Sun thing?
IIRC stderr is captured by sendmail and logged in the bounce message, but admittedly if you're not bouncing that's a problem.
I'd case out the syslog dependency, and use it only when available. Last I looked, Perl's syslog module was... limited. It doesn't even work at all on some platforms -- something about trying to UDP to the local syslogd instead of using syslog(3) through libc. So it's more portable to system out a call to logger(1) if you need syslogging and can afford a fork/exec.
-- -D. dgc@uchicago.edu NSIT University of Chicago