Ducks, Polyester thread USED to be lousy, but today's poly thread is excellent. There was a worry that because it was stronger than cotton, it would act like little knives & cut the fabric. Hasn't happened.
Coats & Clark Dual Duty XP is 100% polyester now - no more cotton wrapped poly. We use it in the quilting program. It doesn't fray and break like the old Dual Duty does. I hate the old DD.
Glad you changed your mind about your block. My first blocks looked better the next day, too. I wasn't happy about how the bobbin work with the Razzle Dazzle looked, but have decided that's how it's gonna be.