Won't comment on EA's quite silly declarations, nor on opinions floating around about the graphical excellence of various games. I'll keep it on one sort of technical issue that emerged:
@Selnor
That wheel rim in the GT5:P shot is really weird, but it doesn't look like it's suffering from low poly count to me.
Look at the image in full resolution, and notice how the weird non-circular shape only happens on the top-left and not on the bottom right. If a circle is approximated with a low poly count, the error happens all around. Plus notice how the vertices between those "polygons" you think you're seeing there are actually smoothed beyond AA, ie again that doesn't look like missing polygons.
I really can't say what's happening there, though, because I have never played GT:P, nor am I familiar with its looks first-hand. Could it be that we're seeing a "vibration" optical effect there?
As for Forza looking "more solid and less cartoonish", that's up to the lighting/reflection, not to the polygon count. Both games seem to exhibit perfect modeling to me.
And @Squill
Does Forza 3 use tessellation in its engine?