A mac running Darwin/OSX is as capable for development as any Linux box. In fact, some would argue, even more capable.

Keep in mind a few things:

• The default filesystem is case-insensitive. Yeah, unlike all boxes in the Unix world. So, there's a few CPAN modules that blow up for that. You can either avoid those, or make a UFS filesystem to mount as needed.
• Nearly any interesting "unix" tool is available either in Fink or DarwinPorts. However, neither of them cover the entire list of interesting things, and installing stuff from both will be troublesome and redundant. And for other things, you'll have to install things yourself anyway (like I build a daily updated version of Emacs from CVS, so that I can get a nice Carbon Emacs that acts Mac-like).
• Yes, there is a Perl community at Apple, and Perl is fully supported on the Mac.
• You can write XCode programs with a natural Mac GUI, using Perl code to implement the triggers, using Camelbones. By You, I mean someone smarter than me, because I still haven't gotten my head completely around it.