I have a couple Canon IPF printers and will get another when I'm ready to spend some money on a new one (trying to resist spending right now). I've been very happy with the Canon printers and the Canon service. Actually, quite impressed with the service as I had one of the original roll-feed gear hiccups occur, long out of warranty, and Canon sent a tech to my home the day after I called. In fact, the part arrived after the tech who had driven over two hours to get to the town where I live, arriving at my home at 8:00 a.m. We waited for the UPS Overnight shipment to arrive, he installed it and returned to his office over two hours away. This was free of charge. I was amazed. Canon treats the 17" printer as they do the larger-format pro printers. Epson may also – I haven't heard either way.
I use the roll-feed a lot, print a lot of matte papers, but use "luster-type" papers for portraits and certain other images. I don't want to organize my printing schedules to accommodate such paper changes, so I really appreciate the no-purge black ink situation of the Canon design. That said, I understand that Epson has worked to reduce the amount of waste for the swap, and kudos to them for that. Still, for me it's a deal breaker. I don't have the data on this computer (I'm traveling) but if I recall the swap costs about $5. If one does this rarely it's not a big deal. But if one might make a couple of round-trips with the MK-PK-MK, change it can add up.
As others have said, the 3800 has been an excellent printer for many users. Epson does a very good job (obviously), but I really wish they'd direct-plumb both black inks. The compact size and excellent output of the printer is lost on me because of this design "flaw". Still, if one is not needing or wanting to use roll papers, doesn't need to swap blacks regularly, or is "space-challenged", the Epson will surely make fine prints. But for the reasons listed in some of the posts above, I prefer the Canon 17" printer.