Matter of fact I do:
Here is a gallery of pics of the CIS connected to my R1800:
http://www.pbase.com/johnj80/printing
Here's one:
Mediastreet has testing with this chemistry that they use in a number of their inks with the Wilhelm Research Institute. They have certified that the inks won't fade for more than 50 years (the extent that mediastreet paid to test it). I can't find the link but it is there if you search their website.
That said, skeptic that I am, I devised my own test. I took a print on Ilford Galleria Smooth Pearl paper of both Epson ink and Mediastreet ink. I put them in my west facing office window that gets direct sunlight up to 9 hours a day in the summer. I covered half the prints with a book and traced the outline on the book with a permanent marker. After about one year (will be a year in July) there has been no fading and there is no discernible difference between the Epson inks and the Mediastreet inks.
I have found that with custom profiles on my papers (I use Red River Polar Satin, Gloss and Matte), I like the results better than I did with the OEM inks on both the OEM papers and the Red River papers using OEM profiles on OEM inks either from Red RIver or from Epson. I presume, but did not waste the time, that custom profiles from my printer on the OEM paper with OEM inks would also be better.
The cost of the Mediastreet inks is about $159 for 4 ozs that is equivalent to 8 cartridge sets from Epson. Even if you buy the epson carts at a discount (best I've found is Atlex), that is a huge savings (8*$11*8=$704 or a savings of $545!). Since I'm on my third set of inks from Mediastreet, that means I'm over $1500 ahead in one year. I'm not a big printer and I was using about $200 per month in epson cartridges before I switched over.
Some say that this would impact the warranty - doubtful and it probably depends on the state in which you live. However, at this rate, I could buy a new printer and still have money left over on each set of bulk ink.
I do a lot of big printing but it is sporadic - The size of the prints I do, would almost guarantee that I could not get through a print without having to change a cartridge. Then the printer goes through a cleaning cycle - wasting more ink - and I'd be running low on another quickly. This way, I never have a problem.
Because I print sporadically - like mad for a week and then nothing for a month or more - I have the normal bubbles in the nozzles. I had it with the OEM carts and it is about the same with the CIS. Normal problems inherent in the technology.
That said, the results I am getting have me tickled pink. I have been thrilled with the prints, the detail is amazing and they are good to go to hang on the wall.
I'm a big fan of Mediastreet. They've been very good when I've had problems, they will do a custom profile for you for free (I have my own gear for that though), and they sell a quality product.
J.