whats your favorite diesel pickup

Cummins is the only option. The 5.9 liter six was designed from the get go for a life of 500k miles. This motor was introduced in 1984 and it's a proven design. 40% less moving parts inside than those off brand diesels. Have you ever seen a Powerjoke or a Duramax with 800k miles on them? There are even Cummins engines with over 1 million documented miles.

Yes. There was a boat hauler on Cape Cod who had 1,000,000 miles on a 1995 F-350 dually. My wife drove an F-550 rollback...when totalled, it had 930,000 miles. 400,000+ on a 7.3 PSD wrecker is COMMON!

Also note: International installed (and warrantied!) the T444E (what they called the 7.3) in medium-duty trucks, school buses, 10-wheelers, and even semi tractors!