I think it matters very little, except that a beautiful pen should have a beautiful nib.
The part you put to the paper isn't made of the main nib material, but something much harder.
The feel of the nib is of course important, but that doesn't have anything directly to do with if it's made of steel or 14K or 18K gold, as there's no rule saying the material thickness has to be the same. So in principle you can vary how the nib flexes without changing the metal used. And in practice you can observe that effect by comparing different models from the same maker with nibs made of the same alloy.
And stiff or flexible nib, that's just a matter of personal preference.
Document created 2002 Jan 21 by UrbanSite main page