In engine design, the odd cylinder configurations are not as smooth primarily because of firing overlap. For example, a 4 cylinder engine fires once every 720 degrees which means there's a "power stroke" every 180 degrees so two power strokes for every rotation of the crankshaft. The power stroke (explosion) can not last more than 180 degrees of the crankshaft rotation (or you'd have knock). So when one cylinder is at BDC (bottom dead center) at the end of the power stroke, another cylinder is firing. There are 2 cylinders firing and 2 cylinders exhausting for every rotation, so there is no overlap or vibration as is the case with any even number configuration. It's smooth.
A 5 cylinder has a power stroke every 144 degrees and since it last for 180 degrees that means there is overlap where one cylinder is firing while another is still in the power stroke. This overlap causes vibration (NVH) but is more noticeable at lower rpms. This overlap of power strokes also means a flatter torque curve so there is a pro to this layout as well. As you add cylinders to an odd configuration (7, 9, 13, etc...) the vibration is much less but still there. There's a reason 5 cylinder engines need large balancers.
Lastly again due to the power stroke overlap, odd configurations typically do not like high rpms. Of course an expensive well designed 5 cylinder will seem smoother than a cheap run-of-the-mill 4 cylinder but with all other parts equal the even configuration will always be smoother.
Since this is diesel, most won't notice excessive vibration at idle and the broader torque curve will only help the natural torque of compression ignition so this may well turn out to be a good design but only time will tell.