The first mat I bought was one of the whiteplastic appearing ones and I was of the opinon that it was hard on the blades. Perhaps we should also consider that we are cutting layers of fabric, and the fabrics can vary in texture and even quality. I htink most mats are made of a self-healing product, and if we were able to find out what it is, we might find they all use the same materials. For some people, the measure of quality is tied to the price of the item. That is not always true.
The amount of cutting, thickness of layers of fabrics, blends (with polyester) could all play a role in dulling the blade. After all, it is a fine, thin blade. (compared to a razor blade and a course beard, I would think the rotary cutter blade gets lots of usage and does a good job.) When I made boutique items I used my serger to sew nylon swim suit cover-ups. The nylon lace would quickly dull the surface of the knife in my serger. I believe there are many factors involved in deciding what dulls the blades, and for me, I like a sharp blade. I now have 3 cutters, I use one after the other until they are all dull, then I get out the WD40 and spray the posts, remove the dull blades and put in new ones. I am happy with my system and after one severe injury, I know that oiling that post is important. There is no need to struggle with removing the blades.