I've also had some similar issues with my epson printers - a 4000, 7600, 7800. The print head have a limited life, and when the one in my 7600 died, Epson wanted a huge amount of money to fix it. I ended up reselling it to a local dealer, who gave me $1500 off on an Epson 7800 for it.
I also share a large format 44" Canon with my cousin who is just down the road. As of yet, the only issue we've had with that is the cutter. It seems some of the stocks we're using - like Canvas - are a bit on the thick side. It's an easy fix though, we just use a knife to cut it ourselves. Otherwise, the machine has really worked well.
I'm not sure what my next machine will be, but I would take a serious look at both Canon and HPs offerings. It used to be that Epson was the on;y company offering printer profiles, and machine made for serious photographic work, but this is no longer true. With the advent of personal spectrophotometers like X-Rite's eye one, and the Colorvision Spider line, you can get great color from any of the three main brands.
Raymond Klass Nature Photography