First of all we have to make a distinction here, are we dealing with a ink jet cartridge with the printhead on the cartridge, or are we dealing with inktank where the printhead is eternal to the cartridge.
After that we must ask, how critical the application is, because if we are dealing with photoprinting, we are asking for exact OEM color balance and resistance to fade. Otherwise, as long as the ink blend matches the printer well, the color balance is less critical.
As it is I have a non chipped Canon and simply refill my own ink for less than half the price of re-manufactured and have better color balance to boot. And its very easy to refill with 100% success. But I also had excellent results with refilled inktanks for Canon printers.
But I never could master the art of refilling cartridges with printheads on the cartridge. And those cheap foil printheads have very limited life anyway. And you seldom save over 50% over OEM and get a high fraction defective to boot. Which is why I avoid printers that use that on the cartridge technology because they end up being no armed bandits.