EDIT: I had meant to write Beige G3s, I don't know why I wrote blue-and-white.

I have both a beige at either 333 or 366, and a blue-and-white (but with a PCI Power Macintosh G4 board, for fixed IDE goodness) at 450, but my commentary above was about the beige.

During its lifetime, I mostly used the blue-and-white with Mac OS X, but that system is also good at Mac OS 9.