I'll second digitaldog's comments above. A large gamut by itself says very little for actual output quality. I'll also note that John's statement quoted is open to gross misinterpretation.
Well it may be OPEN to gross misinterpretation, but the statement I made suggests that based on the gamut plots there MAY be an advantage in the blues.
This topic came up about a year ago in regards to the Designjet 130, where I noted a lack of the DJ 130 in the blues looking at gamut plots compared to the Epson 2400. Neil Snape had maintained that the DJ had a perfectly good color gamut. A friend sent me an image to print on the DJ 130 compared to the Epson 2400. The image happened to have some pretty saturated blues from water in the Bahamas or somewhere. Well guess what--the Designjet fell short (not horribly, but immediately noticeable), the Epson print matched the screen quite well. Both were printed through their respective printer drivers with custom profiles I had made with Profilemaker Pro.
So, my statement stands that the Canon MAY have an advantage in some saturated blues in real world images compared to the Epson, based on looking at the 3D gamut. The gamut maps are pretty close in most other colors, so you aren't likely to see much of a real world difference. That's really all I am saying. I wanted the data to be available for others to see.