I am amazed that this seems to be the only "up front" discussion here around this question. Yes, they do work and exceedingly well. Avoid the ones with sponges in their system heads. Use dye based ink rather than pigment based - better to avoid clogging. They can be tricky to install, often involve cutting or breaking away bits of the casing of your printer, and almost certainly voids the warranty on the printer. But who cares, they almost give the printers away and kill you on the ink refills. I installed my CISS on an Epson for about the same cost as buying one set of ink cartridges, and I've got enough ink for about three years of unrestricted, full colour printing. Go for it! Yes, I know this thread is quite old but I bet others are looking for the same answer.