I installed 
Yellow Dog Linux version 2.3 on one of our old macs today.
I hadn't
ever installed Yellow Dog before -- mainly because they don't have a network install and I haven't
had a CD burner before (and I'm too cheap to buy a CD*). But I have a CD burner now, so I downloaded
an ISO and made a YDL install disk and (after swapping out the broken CD drive), I was able to install
Yellow Dog on a Beige 333mhz G3. What a great experience! Everything just works! Well, pretty much.
It's just like using RedHat on mainstream x86 hardware. I'm encouraged by the experience and may look
into ordering YDL 3.0.
Note: I'm not really too cheap. The real issue is that ordering anything on this campus is a royal pain. You have to figure out who are the MHEC vendors for everything, get academic pricing if available, fill out a purchase request, wait for days (or weeks) for it to be turned into a PO, and then order the whatever. I really try to avoid ordering anything. Sometimes you can't help it.
It looks like one of our new machines ended up with a bad memory module. It had been acting flaky ever since we got additional memory installed. I got the vendor to come out and swap out the module and so far it seems to be working OK. It will be great if that's all it was. The symptom was interesting: it would boot up to the login screen, then die and dump you to a text console login (which is not what MacOS X users expect). Initially, I thought it might be corrupted system files, so I reinitiallized and reinstalled, but it did the exact same thing afterwards.