I just have to say I love it. I pulled my 27' trailer into town today to get it ready for the camping season. The trailer weighs in just under 8000 pounds. Engine didn't seam to have to work to hard to get it going and on hills.
If it wasn't for the trailer swaying, I wouldn't have know it was back there. My brothers 4.6 seems more peppy. I thought it was because my engine is almost 10 years old. I did find out that my truck did have the cam phasers replaced before I bought it. Thats a bonus.
Back when I had my pre-phaser 5.4, we took it over 4000KM to pickup my Dent. My 7700 F150 didn't give a crap about the truck and trailer behind it. I took two of my Chevy biased friends with me, and they were both suprised and thoroughly impressed.