I ordered my HF blades online. 10 packages of 2 each. I have had the same unfortunate results as others have described. I have changed the blades repeatedly and am now into the 3 or 4th package. Each blade has given the same result. They have dulled well before a yard of fabric is cut. After they dull they begin to skip. I have used my sharpener on them to no avail. It is hard for me to get the wheel on my cutter tightened 'just right' for the blades. The blades seem to wiggle as I am cutting. (I am only using one at a time. LOL.) If I tighten the wheel to stop the wiggle the blade is too tight to roll. When I put lots of pressure on the cutter it feels like I am cutting into my mat.
I am making a Bargello and have cut 24 yards of 2 1/2" strips, then cut strips from the panels I made with the 2 1/2" strips. This is enough fabric for a good test of the blades.
I am very interested in the updates about the type of cutter that works best and defective mats. I will use those ideas to trouble shoot further. If I can't find a solution I will not purchase any more of the blades.