aldevo posted previously that Kodak's better at film speed, and your post says otherwise. Which one's true or rather, which film has slightly faster speed? Another question I have is, if both were printed at maximum quality (Kodak on color paper and Ilford on true B&W paper), which one do you think would look the closest to real B&W film?
Plot the curves and the XP2 comes out faster. At least that happened when I plotted them (for a magazine test) when XP2 Super was released; discussed this with Ilford because I was surprised at 1/3 stop difference; and they said, "That's what we found too."
You'd have a hell of a job ranking two first-class prints of the right subject, made by the manufacturers. Nor am I totally convinced that Kodak is better suited to colour paper. I've made a couple of excellent prints of snow scenes (heavily red-filtered) on Ilford MG IV/WT from the Kodak material -- but on a misty day, I found contrast of dark catkins against the mist to be totally unconvincing with the Kodak film.
A lot of it is subjective, obviously (though not the speed), but the tonality is different and is the only reason I'd go for Ilford, for my subjects. If I couldn't get XP2 Super, I'd not be heartbroken at switching to T400CN; but over some decades of using chromogenics, I've come to the conclusion that XP2 Super suits more subjects, better, and prints easier. Someone else might take the other view.
Hope this helps,
Cheers,
R.