Mark, thanks for your response. I think my "pick your poison" comment was a poor choice since it suggested to you that I had to choose between two poor options. That was not my intention. Nor, is it my belief. I believe I am confronted with making a choice between two excellent machines whose printing capabilities are very high - though, per your review comments, not up to par with the 4900.
The 'poison' was having to choose based upon lower importance issues/capabilities such as roll feeder/panorama capability, nozzle clogging potential, imposed margin / print length restrictions (which appears Canon will be resolving), price-at-the-moment, etc.
My question about inks and the chroma optimizer was essentially my attempt at trying to break a tie. Re-reading your review leaves me believing Canon's 11 inks (at ~$60 each) provides the equivalent output to Epson's 9 inks (at ~$55 each) giving Epson the edge on ink cost.
I still don't know how to value the chroma optimizer. I don't recall if your review indicated that the chroma optimizer had been applied to all Canon prints compared / measured with the Epson prints. If they were not, then it is an open question. If they were, then it seems to afford very minor visible benefit while adding cost and complexity.
In any case, if only 1% of the quality of the final print is contributed by the printer, with 99% coming from the quality of the image capture and the image editing, then the decision really isn't very important. Thanks! I can stop worrying about it.
OK, time to clarify and sharpen a few points here. The Epson 4900 has a wider gamut in
limited parts of the spectrum. Otherwise and for a great many photos not needing that extra gamut, there is very difference of print quality to tell between these printers, save to say that both the newer Epson and Canon inksets can reproduce a slightly deeper maximum black than the Epson 4900. I do not recommend buying an Epson 4900 unless it will be in fairly continued use.
There is no way of knowing yet who has the edge on ink costs because the required information to make such comparisons is simply not available from an Epson P800 and I have heard of no intention on their part to make it available. For the Canon printer it is now available, but only for the ink laid down on paper, and not for all the ink used for internal maintenance, which may be considerable - however Canon will not provide tracking information for this aspect of ink usage, which would vary a lot from one user's printing habits to another's. So forget about this and don't try to make a purchase decision based on ink costs - even if we knew them, I am 99.9% certain it wouldn't sensibly sway a decision toward one brand or the other. It is one of those "nice to know" things; however, for service bureaux a more important consideration than for casual printers - but most of them use larger upscale printers where much of this information is provided.
In the same vein, forget about trying to value the chroma optimizer independently of the rest of the inkset. Consider it simply as part of the inkset whose major role, as Canon says, is to expand gamut and dynamic range of the prints. As I said in the review and several times since, there is no option to turn it off. It is always used. The option available is whether to let it spread across the whole print (recommended), or in Auto mode where it activates for the parts of the print with the denser ink laydown. It is costed along with the other inks in Canon's new print cost accounting utility which Pro-1000 owners can now install.
Good that you are now more relaxed about the decision you wish to make - and indeed, the factors you include in the "poison" do differentiate these machines; so you need to land on which set of features best responds to how you want to print.