Thanks for the honest reply and your experience. The 4900 does seem to be the worst of the bunch from all the postings I've read. I do think you're right that the printhead is maybe not often the problem, and I have read that it can be the dampers, or other things to do with the ink delivery system. But I know nothing about this, and since I don't have Epsons, I only read about it without actually trying to absorb any info.
I really do appreciate the honesty about how you have to do a nozzle check, and that time is the biggest issue with this. I remember when I had my 4000 and 4800, I learned that if I did a nozzle check every two days, it wouldn't have to do a clean cycle. I also learned that those nozzle clean cycles would use up 10ml of ink, which was incredible and made me almost not want to print cause I knew if I turned it on, it would need to first waste ink. But I at least liked knowing how much ink was being used. With my Canon 6100, I lost the ability to track ink used on cleanings. With the 6400, I can now access this in the great accounting feature, and although it doesn't exactly tell me how much is used for cleaning, it tells me the total ink used, and how much for each job, so I can always do the math.
I still wonder how your source gets the info about the cost of ownership being just as high on the Canon. I simply don't know where the money is going. It is true that if a printer is owned for 4 years, with the Canon, you more than likely had to already buy 2 heads. With the Epson, the printhead can last longer than the Canon, since the Canon is thermal and will burn out, so if you're lucky to have an Epson that doesn't give you trouble and use it regularly, then you might not have to replace anything. But I really do believe that the Canons are more trouble free by a long shot, and in most cases, all they ever need is a printhead which can be replaced by the user and you're up and running in no time, so at least in the headache department, the Canon has to be much further ahead.