CMY printers only have the three color inks and use all three combined to simulate black. What this means is that these printers cannot handle black text at the same time it is printing a color image. Also, the combination of the three colors does not always get a reasonable black - sometimes you get an ugly dark brown instead. CMYK printers are better. Note that CMYK are substractive colors - by adding more ink you subtract from the light that is reflected so the result is a darker image.
Additive colors are the opposite.
Epson printers are reported to have problems with their inkjet nozzles becoming plugged. The Stylus Color 500 has a self-cleaning mechanism that appears to clear the problem. My old Action Printer 3250 seemed to have this problem, but it didn't have any buttons for automatically clearing the inkjet heads. Many printer manufacturers also sell paper specifically designed for use with their printers. I suspect the glossy paper might not have the problem so bad, and cards for special occasions should be ok too.