Before the 4000 I had a 2100/2200, which uses the same inks. There is no comparison between the two printers, the 4000 is simply in a different league. I found with my 2100/2200 I would frequently get head clogging, not so with the 4000, which hardly ever clogs, even when left for weeks and weeks without use.
The 4000 is big, and built like a tank, it's a real workhorse of a printer. I've churned out full wedding sets on it, and it eats it up, and spits them out one after the other. The roll paper mechanism is excellent, nothing like the fiddly removeable ones on the smaller printers. The paper cutter is built into the print head, so it just works and you don't have to fit any weird boxes, like with the 2100/2200. The paper tray is an excellent piece of design work, very clever, folds up really small when not in use, and just pulls out when you need it.
The ability to print with both Photo and Matte black inks without changing cartridges was appealing to me, and a big selling point, though I find now I have it, I tend to use just one type.
The reduced costs of paper and ink from buying rolls and the large cartridges this machine takes, will in my opinion pay for the printer in quite a short space of time when compared with say the 2100/2200.