I have a G4 Power Mac that is 8-years-old and is duel processor. Running OSX has made it stable. The only big problem I had was a harddrive that died on me and needed to be replaced. Otherwise doing fine.
Big difference between the G4 Power Mac and the G4 iMac. Maybe I just had really bad luck with the two iMacs that I had but then again when mine started acting up it wasn’t hard to find people with the same problem.