I've read that the 7.3 is designed as a truck engine. They're expecting considerably longer life than the 6.2. I don't think it's been out long enough to know in the real world, though.
Ford went back to the basics with the 7.3. It's an OHV design, not DOHC. Said you get better low end torque with the OHV and that's where the 'truck design' came about. Ford is putting the 7.3 in trucks up to the F650/F750 series.
Also, a buddy has a new F-250 with the 7.3. He really likes it.
