Both excellent and for sure the 7.3 was far better than the POS that replaced it (6.0), darn near as bad as the GM garbage from the eighties conceived out of a Olds small block I believe
FWIW my '02 Duramax was flawless, combined with the Allison transmission it was a beast, over 99,000 trouble free miles when I traded her in. Towed my race car in the summer and sleds in the winter.