Is there a significant difference between using a loaf pan made of this materials?
Sandwich or quick bread has different heat requirements than artisan breads.
Artisan breads require a blast of high heat and humidity right from the beginning. They are usually baked on flat, preheated stones that store a lot of heat.
With breads baked in loaf pans the bread is proofed in the pan which is obviously not preheated. The goal is not a blast of high heat but generally even heating.
Stoneware and cast iron will hold a lot of heat but that isn't very useful for this type of bread. The big difference that a stoneware loaf pan will make is in the bread's crust. Unglazed stoneware will let some moisture escape during baking. Stoneware loaf pans are often used for dishes other than bread such as meatloaf where the even heating and heat retention when serving is valuable. Bread baked in stoneware will be crustier in the area covered by the pan than bread baked in metal. This is a more compelling advantage with quickbreads. In my opinion sandwich bread doesn't need to be crusty.
Metal bread pans are cheaper, lighter, and less fragile. They won't even out any heat gradients in a sloppy oven. If you know your oven is unreliable consider getting a thermal mass (such as a pizza stone) to even out the temperature.
I haven't used a cast iron loaf pan but my first inclination would be to use it for southern-style cornbread. This type of cornbread is normally cooked in a cast iron skillet. The pan would be preheated with hot fat and the cornbread batter would be poured in. The stored heat in the pan would fry the bread before it rose and set. I don't know why a cast iron pan would be used for normal bread.
I have baked bread in both stoneware and in cast iron loaf pans. In my opinion, cast iron loaf pans win hands down. The crust comes out a beautiful, even, golden brown all the way around the bread loaf. I will not bake bread in any pan other than my cast iron loaf pans.
As far as artisan breads, they bake as well in cast iron as they do in stoneware. You can put cast iron in an oven at the recommended temperatures needed in order to achieve the crust so desired in these types of breads.
Given that they are used in the same way, thermal conductivity is the only difference. This is the rate in which heat is transferred from the oven through the walls of the pan to the bread
The bread exposed at the top of the pan will cook using the available radiant heat of the oven
The bread contacting the surface of the pan will cook using the heat transferred through the walls of the pan. If the thermal conductivity of the pan is low, you will not get a hard or browned crust. Earthenware, stoneware, and glass have a much lower thermal conductivity than metals used in pans
Stoneware by definition in non-porous, traditional earthenware is somewhat porous. Most modern earthenware (from Asia) though is effectively non-porous. Either way, the ability for stoneware to be "porous" to steam in any quantity will be very limited in the short trip in the oven. If you want surface stream escape use a perforated metal pan such as baguette makers use
Note: baguette makers use these sort of pans so stream can get to the bread, not escape from it. They use steam ovens to promote "oven spring", which is the process of using steam to keep the bread crust from hardening while the bread still rises internally in a hot oven. A lidded pan, cast iron or other material, generally simulates this effect