Is Ubuntu a realistic alternative to Mac OS X? For some it could be, but your experience will differ if you have a PowerPC Mac or an Intel Mac. But does it match up to Mac OS X?
I am a firm believer in getting the very most out of older hardware – part of the reason I like and write for Low End Mac. With the move to Mac OS X 10.5 Leopard, Apple cut out a lot of older computer users and began a slow death for the G3.