My TV is a 2004 F550 with a 6 liter. I bought it used but knowing its history. The original owner pulled an 8 horse trailer between Ontario and Kentucky. I got the service records with the truck.
I did a full filter and fluids service on it as soon as I got it. It pulls my Sterling 32RL with ease. I had to drive WOT a couple of times and it is amazing how much power you get. Like any vehicle if you take care of it and don't drive the s--t out of it they will generally behave.
I am happy with it and got it for a price that if I need to rebuild the motor then I am only out the camping time then money I have already factored in not having to buy new.