I've had quite a few problems with my F-450 7.3 Powerstroke, even that this engine is rated as the legendary Ford diesel.
Here are a few common and well known issues:
Fuel system: Wrong high pressure fuel connectors before the fuel pump leak air into the system, because they are made for high pressure but not vacuum. Also the fuel component in the tank is wrongly designed to generate air in the system due to the close position of the sucking and returning fuel lines. There is an aftermarket modification called in-tank mode that eliminates the problems. External fuel filter and bigger fuel line (3/8"), high pressure connections before the fuel pump are replaced as well. The upgrade is $175
IDM (Injection Drive Module), this is a device (also called computer) which is simply an inverter. It supplies the injectors with high 115-120v voltage. Ford has managed to put it under the fender where it gets constantly wet which leads to fail prematurely. Rebuilt one is $200
Injector's wire harness: For some reason the harness eventually gets bad connections which leads the truck to shut off instantly. I am not sure of the price of the harness but it shouldn't be over $50-60.
Glow-plugs: very often problem
Fuel Injectors: Another common problem and unfortunately extremelly expensive. If Ford dealer will replace them, be prepared for $4000 and up.
Fortunately there are rebuilt ones for around $100-200 per piece (8 total) plus labor $400-600
Often there are just worn out o-rings ($80-100 for all 8 injectors), but people who are not technically inclined fall for the mechanics trick and have the whole injectors replaced for tons of money.
Overall the truck is a Beast, but it has its many many manufacturer's defects.
If I wasn't concerned about clearance, I would go with Isuzu flatbed. Isuzu NPR Diesel trucks RULL. All my sweepers are Isuzu NPR and they take a lot of abuse. They are made to last and not complain!