You'll find the difference between the engines in hill climb. I guess you'll cringe when revving a gas engine with such a heavy body on steep gradient. But then it will suffice, since you know you won't be pushing a people hauler to track speeds.

But despite the shortcomings of the VVT-i engine when compared to the D4-D, VVT-i is the choice because you only need to change the oil & filter every 7000kms.