Re: Why?
my feeling on the relative speed of linux on the same hardware is not necessarily up to date. it was true when I ran a hackintosh. :-) and it was true on that G4 Mini.
opencore for keeping at least Intel machines running on the latest (until the latest doesn't even support Intel) is something I look forward to trying when my last Intel mac falls out of official support - otoh i might well be sticking linux on it then for preference. i might even do it sooner though: I run PVR software that needs linux on x64 to run (v4l driver support needed), and it failed to work reliably with that linux in a virtual machine, but the old PC tower is just too noisy to leave running these days.
macports is a name i haven't heard in a long time. the cool kids use Homebrew these days. first thing i do on a new mac. (I lie: second thing, after updates) ;-)