All my epson printers have used epson ink - the cartridge(s) supplied with them when they were new. Despite (empty) threats from dealers that I would void the warranty, all my other ink has been purchased from
http://www.tonezoneuk.com : - if SD doesn't mind me posting the link. I have never, (so far) ever had printer trouble that I can blame on my ink supply and I have been using this source for years and years and years. I haven't had colour balance problems when printing pictures either.
Bhan-Jeaux's advice is also absolutely correct. I like the way we can defeat the money making schemes of Epson and the other printer manufacturers by buying our ink elsewhere or refilling our own cartridges!
When you've done your research you may well find that this way, Epson printers give the best value for money!
P.P.