I went to Kaye Englands retreat. She told one gal to make two blocks using the fiskar mat and one using the olfa mat. there was a difference! the rotary cutter wobbles with on the fiskar. One other thing we learned was NOT to iron your blocks as you go....finger press. It was HARD to do but I am sold!!! my blocks come out perfect without having to trim. When you finish the block....then you press.