Which is the better diesel?

I was wondering what are the pros and cons of a 1995 GMC 3/4 4x4 diesel and a 1991 Ford f250 4x4 7.3 diesel. Also wondering which one i should get. The ford has 158,000 miles where the gmc had 240,000 miles. the gmc was used to haul hay during the summer and the ford was just for driving. I want to know which one gets the best fuel mileage and the one that is the most dependable.