I'd recommend giving OS9 a shot on that G3, if you're not that fond of OSX. Classic Mac OS has its own issues, but it's much less resource-intensive, more flexible (OS8-9 don't have quite the amazing third-party system-extension ecosystem that System 7 did, but there's still some interesting things you can do with them,) and seems to me to be more of a coherent, unified system than OSX, which despite its technical merits is basically a Mac-like UI and a custom library selection grafted onto BSD.