McPherson was a star in HS, about avg in college (great TD to INT ratio, but only 51% completions), and about average in the AFL.
Orton was named as the 2nd best QB in the nation in HS by Superprep (7th best by another scout), set school records and named to several top lists by sports publications and scouts while in college. His TD to INT ratio isnt as good as McPhersons, but his completion rate is much higher. He's also tough as nails. His ability to play through pain is reminiscent of Brett Favre. He needs to gain some more strength, and as with any QB taken on the 2nd day of the draft he will need to learn a year or two before starting.
Overall though, I would take Orton over McPherson any day of the week and twice on Sunday (which of course is the day that matters)