I have the T444E on my 28 foot dog nose bus. Mine is a solid V8 - 210HP engine.
I just drove it 3000 miles from Florida to Montana - and it was wonderful.
There was enough power to go up and down some decent hills while pulling my Subaru.
11.58MPG though Texas and 9.83MPG through Colorado and Wyoming.
I know some people all seem to have their preferences - it largely depends on where you will be driving. More power doesn't always equate a better engine. A well maintained engine may last 200K miles or 500k miles or 100K miles.
I know people living full time in their bus and happily traveling around the country with the T444E, T466, Cummings, and even the Mercedes (Freightliner).
- Roger (Dog.Rescuer)