There is definitely a difference in the performance of different ferro rods (not always dependant on cost)
.There is however a much bigger difference in the performance of the striker used. Some of the cheapest ferro rods work absolutely fine if you use a good striker, the little bit of hacksaw blade covered in Red or Green paint is not a particularly good one, nor is the spine of many a knife. The best strikers I have found (and they will work fine with the cheapest of ferro rods) is a good piece of glass or glazed pottery even a nice sharp piece of flint.
DB