Don't like the fact that Canon appears to be significantly less archival from the limited available data. On the other hand, concerned about potential for clogs with the Epson (humidity can get quite low in Los Angeles), although could easily set up Windows to make a scheduled print every few days.
Print quality of the 6300 is very good, and while the new printers have a slight measurable edge, detectable differences would be difficult without direct side by side comparison. I guess the printer is starting to age and the thought of have to replace the second one might make the investment in a new printer a worthwhile consideration, but replacing the printhead is certainly a logical conclusion.
Regarding longevity, yes it seems Canon for some inexplicable reason took a step backwards with the 2000 and 4000. Odd that Canon and Epson have switched positions, with HP still at the top. I guess Canon users can approach it much like Epson users have, and be satisfied with the fact it's still good and far better than chromogenic prints at this point in time.
The p series Epsons seem to have made significant progress regarding missing nozzles. I no longer keep a humidifier going, and winters in Utah with forced air heating are extremely dry, yet I seldom need to address a missing nozzle in either my p5000 or p9000. The real difference is the Canon still does a good job at doing this on it's own and really not bothering the user, with Epson I still perform manual checks and don't really let the printer manage this even though the auto nozzle detect function seems to work very well and not really be plagued with false positives. I'm about to turn this feature on using the occasional setting to see how well it really works.
I think the Epson paper handling is better than the Canon, skewing is pretty rare and the straight paper path is nice. Obviously the issue of MK/PK could important if you change inks a lot. I change mine out sometimes and the new setting to use less ink seems to work quite well, but it still takes some ink to change them.