Actually your cost estimate may be a little on the high side, but by all
means it is vastly better than OEM ink prices or even the cost of third
party tanks. I have an s820 which has 6 tanks vs. the 4 in an i850. Both the
s820 and the i950 use the same BCI-6 tanks. BCI-3 as in the i850 and BCI-6
tanks are identical in size and capacity. The only difference is ink
formulations which are different for the two types of printers. Both the
supplier you reference and the one I use appear to use bulk ink from
Formulabs which is one of, if not, the best maker of inks. Because I
purchased my ink in 1 pint bottles (480 cc's) that works out to 2880 cc's
for a set of six bottles. I can usually print about 40 full coverage 8.5 x
11 sheets before needing to refill when the first low ink warning pops up.
At that time I install my entire #2 set of cartridges and then refill the
entire set #1. Two of the cartridges will usually take 5cc's to top off the
ink reservoir, 3 will take 3 cc's and one takes 2 cc's. This is a total
consumption of 21 cc's. I paid less than $70 U.S. incl shipping for the six
pints which works out to about 50¢ per refilling session after printing 40
sheets. My net cost is approx. 1.2¢ per sheet. Ink purchased in smaller
quantities will cost more per ounce, but by any estimate it is a great cost
savings. I do a very large amount of printing and have easily saved the cost
of several printers since the first of the year. The i950 should be
equivalent in consumption to the s820, so the original poster can easily get
an idea that even buying some of the most expensive bulk refill inks, his
costs per page will be extremely low. I know he was asking for comparisons
on Canon and Epson models, but because of my total satisfaction with Canon,
I won't even consider any other inkjet.