I have two epson printers that are useless for printing serious prints. My house was broken into a few years back and the window they decided to break to get in just happened to be the one both of my printers sat in front of. The printers have glass dust in them, so not so good for printing quality prints.
For quick down and dirty printing just for myself or for give aways to friends I print to Sams Club.
For my customers or sell prints, I use H & H Color Lab, my largest prints with my D70 and D300 have been 20x30.