If you're towing, stay away from the 5.4. In my opinion. If you're a flat-lander like me, well, it would be OK, but anything more than that, it'll struggle with a heavy trailer.
The V10, is a PI-head engine, and would do the job more easily, and use LESS gas when hauling heavy than the 5.4.
The 460, well, I dunno. Never owned one, but I can relay what I've heard. They suck more gas, doing the same job as the V10, and generally don't last as long. But that's anecdotal.
It really depends on the PRICE of all those trucks. I can't imagine the 460 being very expensive compared to the other two
