NPR or Truck Body? Pros and Cons

I have been looking for a decent one ton or larger flatbed, and I have developed a few questions. I see the NPR style (W3500 for GM) and I am trying to figure out what the pros and cons of one over the other. For instance the NPR obviously have an advantage to not having to judge distance in the front because of the engine bay. NPRs also have a four cylinder diesel as opposed to an eight. In theory they should use less gas and have less moving parts to break. Even though the engine is beneath the cab it does not seem difficult to access. Now, a truck body with an eight cylinder diesel, once again in theory, should produce more horsepower and torque. I have taken note that it is incredibly difficult to get an NPR in 4x4, which could prove useful in oilfied hot shots. The prices are up and down for both. At the end of the day it pretty much levels out around the same, at least in my opinion. What are your experiences?

 

Long story short does anyone have an NPR or similar truck, and sees something that makes them better than any old one ton truck?

 

Ok, that is what I was trying to figure out. I have seen them as flatbed, but never towing anything. It has been pretty tough finding specs on some trucks.