My 2000 Volvo 610 had 528,000 miles on it when I bought it over 2 years ago. Cummins dynoed it and gave me a 200,000 mile warranty on the engine. the trans has a 750,000 mile warranty.
Like others have said - not for everyone, but for a fulltimer it sure beats anything else I could tow with.
If you want general info on HDTs and choosing between them and MDTs check our website, (in sig), and also
www.dmbruss.com