I am looking to buy a 2004 V10 f350 or 2003 6.0L diesel f350 but have heard nothing but bad things about both engines V10 gas hog with no power and the 2003 - 2005 6.0L problems widely known. Considering nothing else is available in my price range, which is worse/better?

If you commit to performing great preventive maintenance on the truck, I would take a chance with the 6.0L. Be sure to only use SAE 5W-40 full-synthetic heavy duty diesel oil in the engine, with a Motorcraft oil filter. Change both fuel filters (Motorcraft, again) and replace the air filter. Also, use Mobil 1 Multi-Vehicle Synthetic ATF or Amsoil Universal Synthetic ATF in the transmission and power steering system. Several recommended oils and other suggestions are provided in the links below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-8.html#post1415281

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-10.html#post1923468

You can likely get a "buy" on the 6.0L--money saved can go towards any future repairs. This advice assumes there's no major difference in mileage on the trucks. Review maintenance log and have a qualified diesel engine mechanic examine the truck before buying it.