While OS X does not natively support the Pioneer 108, that doesn't mean it's incompatible or unusable. You just have to use Toast or some 3rd party burning software with the drive.
The Pioneer 108 under OS X 10.2.8 with Toast should work just fine. You won't be able to use the drive with iTunes, iPhoto, iDVD, or any other Apple-specific application, but the drive should work fine otherwise.
I have a Pioneer 108 in a B&W G3 running 10.2.6 and have not used PatchBurn, and Toast recognizes the drive and burns to it just fine. I can't use the drive with Disk Utility or any of the "iApps," but other than that, it works perfectly.