I have the 4.6 in my 2004 supercab Heritage. Its a 4 x 4 with the trailer tow package, and it pulls my travel trailer (5500lbs) along pretty good with gas milage around the 13-14 mpg range. But again our gallon is a little bigger here in Canada.
Sailorman3

 

I test drove both. I was trading in a Dodge with the 5.2 V8 and I liked the power it had. When I test drove the 4.6, it felt a little weak compared to the Dodge. I knew that I wouldn't be as happy with the 4.6 as I would with the 5.4. Plus, I got a good deal on the 5.4 that I wouldn't have gotten on the 4.6, so it was well worth it to me to get the 5.4.

 

Did not have a choice. I wanted an 8' bed SCAB = HD package = 5.4 l. I like the engine though.