I think compatible toner has come along way and should be on par with the genuine ones.
From what I have seen, there's 2 types of toner for the Oki 9xxx range, a glossy (like the original) and a dull matt one. The glossy one is the same make up as Oki's and more uniform, unlike the matt one, which is rough and not suited for high res printing.
You could try just using a refill toner bottle to save some money, as for the chip, I think there's ways to bypass them, or failing that you can just buy a replacement chip.
I'd ignore all the warnings people have about compatible cartridges.
The main issue with quality will come from the OPC drums and can be expensive to replace. Now if only you could buy cheap OPC drums I think you could beat most prices on high end digital presses (With reasonable coverage), without having to invest a massive amount of money in them.