I think it is funny as to how you guys sit there and begrudge a 6.4, you spill "facts" that have no basis, just because you dont like fords or whatever. The true facts are this, with a 6.4 you can have 600 hp at the wheels for $1200. You can not do that with a dodge or a chevy period. With a ford the 5r110 will handle 600 hp all day long, every day. Neither a 48re or a Allison will handle 500 hp stock. The 6.4 is way way quieter than either the duramax or cummins. I get a real world 25 MPG (imperial gallon) hand calculated, and I can run low 13's without banging on it (no boosted launch) If I was to bang on it I know that I could run a high 12. Tell me what mods you would have to do with a dodge or a chevy and run 12's, certainly more than 1200 bucks.
As for repairs, every one out there breaks down, I dont care what luck you have had with your particular ride, every brand has those similar stories, I know guys that have POS 6.0's with over 500k on them. And we all know that the 6.0 was not a good engine in a ford.
I have a unique posistion, as that I have owned all brands, and have experience modding all of them.
I can say this with all certainty, this ford is the best truck I have ever owned. The fit and finish is the best, the ride quality is amazing ( I admit not as good as the chev, but I also have not had to do a wheel alignment on it yet either, I was on 2 with the chev by this mileage) but heads and tails above the dodge.
In summary, I think it would be a monumental waste of money to change out a 6.4 and put in any other engine. It would cost 12 grand minimum to do the swap, and you wouldnt have the same power, smoothness and as always when you do mods like that there is going to be lots of little bugs to work out.