I use Intel where I have to, but I'll switch my PowerPC Macs to Linux before I toss them into a landfill.
In my experiences with a few different PPC Linux I would say none are faster than OS X 10.3-10.5. I have run Yellow Dog Linux, PPC Linux and Ubuntu on PowerPC and compared to X on the same machine I would rather use Mac OS.
Linux on PowerPC in only really logical if you need or prefer Linux over OS X.