Although I haven't used this blade for much yet, I did test it and it appears to be working just fine. It is true that you shouldn't return the blade over the cut a second time as it does not follow exactly.
I would definitely recommend this blade to anyone. I love scalloped edges and it's hard for me to cut straight with the decorative scissors. This makes it sooo much easier. I've used it for layouts and cards. The only reason I rated it 4 stars and not 5 is because sometimes you really need to press down at the end or it doesn't cut through the cardstock completely.