atgreene,
I think we have collectively decided the 550 is not the better choice for our original poster. I do think, though, the if the heavier-duty Ford trucks are coming with the 6.4L diesel the power question is a wash. The frame I do not know about, but I know Ford has done suspension and steering upgrades to their truck since 2005. When Builder wrote his original response he was comparing his 1999 550 dumper to a newer 4500 or 5500 GM mid duty. I sold my Banks-equipped 7.3L 250 earlier this year and got a new 2008 6.4L. My old 2002 250 was straight line faster due to its heavily modified engine, but comparing it to my new one in ride, pulling efficiency, handling and turning radius, there truly is no comparison. The new truck blows my old one totally out of the water in this area. It also handles and steers much better than any pre 2007 heavy duty pickup from Ford. My point here is that Ford has greatly improved many things on their lighter duty trucks and I assume they have done so on the heavy duty models also. The other question I have is it seems the 4500 and 5500's are really more in competition with the F650 Ford, not the F550. I do not know if this is a numbering issue solely but to some degree we are comparing and apple to an orange. For heavy hauling, etc., I too feel a 4500 or 5500 GM truck would be a better choice as I have never been enthused about the F550 Ford. But, in lighter duty trucks.....well that might be a different story. Just like we would all collectively do with someone buying a tractor or other piece of equipment, I would encourage our original poster to see if a dealership would have a salesperson bring a truck out and let him drive it and check it out--as much as allowed. Many dealerships do this for commericial purchasers because they want repeat business from them. Perhaps he could check into this also.
John M