i currently use a cis kit , and i have done for around 2 years now.
cost of running one of these is amazingly cheap.the downside is if yor printer does brake down and you phone the manufacture they will not repair it if they find out that you have used one of these kits.
but i know when it happned to me with my epson, they located the closest computer repair shop to me ( must have a contract with epson) took it in and they rapired it for me for free
other than that it's a great buy saves alot of money.