The Hetzer was lighter and did indeed keep the Skoda plant in production and used fewer resources. While a bit shorter, mobility favoured the JgPz IV (28mph road speed, 15mph cross country vs 16mph road speed, 9mph cross country for the Hetzer) because of the 300 vs 158 bhp power plants for their respective weights. However mobility mattered a bit less once the war turned to urban defense for the Germans. Those two tank destroyers were both mobile & concealable enough for hit-and-run in urban warfare. They were not simply mobile pillboxes. The nose heaviness was a problem for the later L/70 gun variants of the JgPZ IV, not the early interim L/48 gun-equipped, mainly because of the longer gun overhang. That was fixed by having the two road wheels on the front bogey completely made of steel rather than being rubber-rimmed. Protection favoured the JgPz IV (for example 80mm driver plate thickness vs 60mm for the Hetzer) as it was about equal to that of the later Panthers.