I run a 97 NPR with the pre-turbo engine. I roll at...lets see...(gets at calculator

metric to imperial) 21,000 lbs, Truck Trailer and Excavator.
Reliabilty and fuel economy are the biggest factors here and the ISUZU is so far ahead its not funny. I typically do better than (sigh, calculator again) 18mpg. The build quality is excellent but the Japanese are (just like their cars were 20 years ago) only just getting around to doing something called comfort in the cab. Late models are improved and most dealers have an option for seats with air suspension.
The power issue is much a factor of what you are used to and what you have grown up with. My rig aint doing much on hills (its pathetic) but it stays with the traffic around town no problems...and thats what I use it for..its a town truck. That year/model is infamous for lack of power. 05 onwards has heaps more power but the Japs build them to pull their full load, all day every day. They acheive this with gearing and keep it economical. Do you really need 8 cylinders, 300 Hp and 8mpg to haul 4 tonnes around a city???. In the 2nd Hand market Hino generally has more power pound for pound against ISUZU.
The cab/over thing is also a matter of what you are used to...some don't like it but servicing and maintenance is an absolute breeze...simple and everything accessible, just tilt the cab. I had a look under the bonnet of an 07 F250 the other day....what a nightmare. I changed the water pump on my Isuzu in well under an hour??. Its also worth noting that NCAP rates most late model cab/over Japanese trucks as better off in a frontal collision than 2500/3500 size long nose pick-ups.
It could be a matter of whatever turns your crank.......but with Diesel prices what they are...I'll upgrade to a new ISUZU when I've flogged this one into the ground. It hasn't got twin chrome stacks and big V8 sound but hell it gets the job done.
My two bobs worth...
