Decisions....Gas or Diesel

I had a co worker that had an early Duramax shortbed (1 of 2 made!, even had the unique rear wiring harness part number to prove it) , he claimed he almost got 40 mpg empty on flat desert highways. Diesel out here in CA is about .10-.20 over gas now but hauling I believe still gets you better mileage over gas. Darn M.A.N. injection system cracked an injector and hydrolocked his motor..twice! Yes, 2 factory replacement blocks were installed. Dealer was about to buy the truck back off him so they could get it off the warranty books. 16 quarts of oil at >$10 a pop? F that. I thought replacing 4 gas O2 sensors was bad.....came close to buying a 50 mpg Diesel 8 years ago...a diesel VW 'Caddy" truck!