Buying a new Diesel Pusher
Diesel pushers with the rear radiator configuration often have problems with adequate cooling.
The side radiator configuration does a better job of moving the cooling air through the radiator.
I owned a National RV gasser for 6 years and can say nothing bad about it. However, the Tradewinds DP with a Cat engine had engine cooling problems when operating in the desert.
We chose a Newmar Dutch Star Diesel Pusher due to percieved better quality.
The RV Consumers Group is a reliable source of information, even though strong biases show up from time to time.