So far, I am very happy with the tires. Quieter than expected on the freeway and seem to perform well off road. No flats on my 2k mile trip to Baja. I rotate them religiously and don't see any chunking or excessive wear.
As far as gearing, the 4.6 seems to be handling them fine. I also think I am getting about 16-17mpg but it is difficult to get a precise measurement since my odometer and computer are off about 20%.
I will post some articulation pics after my trip to Death Valley next month. I have some removable sway bar links on the truck now which help with road performance. Without the links, the front is quite 'wobbly' in the turns.