I've had sporadic luck with my HF blades. The first one fine but lasted less than one quilt's worth of cutting. The second was junk right from the get-go. It kept feeling like I was rolling it over a bump, like a fold in the fabric. So I tried it without any fabric and it still felt like it was rolling over a bump plus it skipped in a lot of places. The third is in my cutter now. I've used it for about 16 blocks' worth of squaring up and it's starting to skip. I have to run it over the fabric 3 or 4 times before it gets it all the way cut. So I don't think I'll bother buying them there anymore. I'll wait for a coupon or a sale at J's.
btw I did not use any kind of blade or scissors to open the pkg so I know the blade wasn't nicked, at least not by me.