I'm printing with a 7900, mostly matte papers, occasionally photo papers, no canvas. I purchased it in December 2008 which means end of this year will be 7 years on this printer. I did purchase the 3 years of extended warranty but never had to use it for any repairs. Last summer I replaced the head and Ink Selector (dampers) as a result of electromechanical failure in the head. (Up until then, there were zero issues requiring any kind of repair.) I did the head replacement myself since I have worked on similar equipment in the past and have the necessary tools and background. After doing all the service adjustments required after replacing the head, my printer is actually more "tuned in" than before the head failed.
PROs: I love the output quality on this printer. I think the dithering is maybe slightly better than Canon/HP, but I also feel the average viewer or print purchaser would never know the difference. And like other posters, I also feel Epson has the best paper handling of anyone. And while I haven't yet ventured into using QTR (I do mostly B&W), I have plans to do that and so I like that I have that option. Having done the head replacement and studied the internals, I feel like now I know this machine and can fix most anything that needs attention as long as I can get the parts.
CONs: Yes, it is inconvenient and wasteful when switching blacks. But I'm not doing that often so for me the inconvenience and ink usage is acceptable. I"m definitely not happy that Epson inks are behind Canon and especially HP in terms of neutrality (blacks) and longevity. I'm encouraged that Epson is trying to address this in their new P-series printers (Yellow especially). I wasted a lot of ink leading up to the realization that my head had failed. I wish there was a more deterministic troubleshooting workflow (and even logic in the firmware) to help quickly identify when the problem is the head; it would save a lot of people a lot of time and money.
Would I buy another 7900 or 9900? Maybe. Right now my 7900 is "the devil I know" and I tend to like to use tools which I fully understand and can master for maximum quality of work. But I am hopeful that Epson will extend the P-series into LF (24', 44", 64") and bring additional innovation. I'm hoping I'll get at least another 4-5 years out of my 7900. When the time comes I would likely look first at the P-Series LF printers from Epson, assuming they do offer something in at least 24". I would certainly also look at anything new from Canon or HP to evaluate the current state of innovation and reliability in their offerings. One thing is certain: It is possible to produce stunning work from any of these printers. I've seen it.
Dave