Hi Ian,
Sorry to hear about your problem with the 3880 - kind of surprising given the reputation of that printer being the least troublesome of the lot. Anyhow, as you say, life is life and one must look forward. I assume you've read the reviews from both Keith Cooper (Northlight Imaging) and me (this website) on the performance of this printer. Keith, compared to me, focused relatively more on the mechanicals and me on the characteristics of output and handling of image editing to suit this printer. I think you'll get an appreciation between the two reviews that the P800 is a fine printer. That said, both of us had review units made available to us before the final version and we had to return them to Epson, precluding a long period of stress testing, so neither of us, or I daresay anyone else, can yet have a definitive view on clogging or long-term performance stability, save to say that while I had mine, it worked just fine. For the week or so I had the prerelease unit I did not experience paper feeding hang-ups from either the top feed or the front feed, and I tried both with various thick-ish papers (Ilford Gold Fibre Silk, Epson Hot Press Natural) and thinner (Epson Premium Luster or whatever they call it now). When using the front feed you do need to leave some space behind the printer. The noise level I found comparatively low, compared with my 4900, for example. If I were in the market for a new printer, the major feature that would swing me toward the P800 is the tremendous DMax - produces the blackest blacks I've achieved in 15 years of inkjet printing. Anyhow, you can read-up on all of that in the reviews. Epson claims the longevity of Yellow has also been improved. As for the 64ml ink fill - multiplied by 8 that is still a very large amount of ink - you can make a great many prints before buying a cartridge, and from what I'm informed, very little of it ends up in the waste tank on initial charging. Most of it is in the ink delivery system.
I can't advise whether you should buy a Canon or an Epson or anything else, but remember you are in the 17 inch segment of the market where choice of professional printers is quite limited; I remain to be persuaded that any other manufacturer produces a recent vintage printer of this quality in the 17 inch professional range.
(typo corrected)