I've only used ink from two sources - one was a universal kit from Wal-Mart. While it worked, the colors were quite a bit different (red was still red, just a different shade). And I only got one and a half refills out of it
The other one was from Cinphi. I've not needed to buy a replacement yet since they gave me so much more ink than that universal kit to start with - and for the same price. They also supply different ink for different printers depending on what the specs call for. Their kit had good instructions, gloves (use them the first time anyway) and a HUGE bonus over the generic kit....
....4 syringes. While that may not seem like a big deal, it's a great time saver compared to filling one chamber, cleaning that syringe, filling the next, cleaning the syringe again, and so on. Each time you risk water contamination in the ink. With one per color you do it all at once, clean them and let them air dry.
Anyway, I had good experience with their kit. The universal one worked, theirs worked better (for me).
Cinphi if anyone's interested. Also have bulk ink in case you ever need 16OZ at once!
--Mc