There is another interesting quote from this site.
"With photo-quality inkjet printers now widely used for the commercial production of images, many third-party ink companies have introduced bulk-ink feed devices that provide a continuous ink supply (CIS) to the printer, eliminating the need to change cartridges. The potential reduction in consumable costs is enormous, equaling about a 70% savings over buying original cartridges. These devices are bad-mouthed by printer manufacturers because they take away a valuable revenue stream, and are claimed to be unreliable, difficult to install, and, worse yet, damage the printer. In some cases, this is true; there are some poorly made systems out there. However, I believe that a welldesigned bulk feed system can actually increase the printerís reliability. The reason a printer requires several cleaning cycles after a cartridge change is because of air ingress into the print head.
Here are some tips when choosing a bulk ink feed system. First, find out if the system comes with pre-primed ink cartridges. A lot of these systems are supplied empty (the ink is sold separately), and the user must first fill the cartridges using syringes or a small suction pump.
Second, determine if installing the system requires any major modifications to the printer. Awell-designed system shouldnít require any hole drilling or cutting of the printer covers. (Remember, you may one day need to return the printer for warranty repair.) Finally, donít consider a bulk ink feed attachment unless you regularly do a fair amount of printing. If you only do a couple of prints a week, these systems are not for you since the ink in the reservoirs will go out-of-date before you use it. A good rule of thumb is, if you use more than a cartridge set each week, a bulk feed will save you money and work reliably. "
This is an article, written by the president of a third party ink suppliere (Lyson). It doesn't really sound fishy.
If anybody finds something fishy, point it out.
I don't have enough experience to judge this, and stay with original inks and quality paper as for now.
But, upon reflection, ink is not rocket science. What is important, is the knowledge about how a certain ink and a certain type of paper react. As long as you don't have this information, any ink is worthless, no matter if third party or OEM.