Ther only area where Canon OEM ink is superior is in fade resistance. And that difference is not all that great---with the photopaper you choose being of more importance. But when you consider that an 8x10
photoprint will cost the user almost a dollar in ink consumable costs using OEM ink---anyone doing volume photoprinting is going to be spending fairly big bucks.
When one talks about the BCI-3&6 cartridge lines---or even the chipped CLI-5&8 cartridges---Canon OEM ink vended in the form of OEM cartridges costs something on the order of $2500/gal for text
black and about $4300/gal for the colors---and thats cheap when compared to what HP and Lexmark charges----but top quality Canon refill ink with very close to Canon OEM color balance can be had retail from anywhere from $100 to $200/gal depending on the quanity purchased.---the gallon unit is just an arbitary unit---its the ratio that counts.
At the nifty stuff forums concenus favorite inks are vended by MIS, formulalabs, and hobbiecolors.
Price is often a poor predictor of quality.---especially when you get into mass vendors of cartridges on ebay or the like. Which is why I look on the nifty stiff forums for ink ratings.
But you can evaluate quality three ways (1) Safety---always get an ink blended for your type of printer--never get a generic ink advertised to work in all printers brands. (2) Color balance---very important if you do photoprinting---not as improtant if you are just doing general printing. (3) Fade resistance.===where Canon OEM has a slight edge.