I just shave with my fatboy for the first time today and felt that it was less aggressive than my slim. I'm not sure because that was my first w/ the fatboy and have only had 2 with the slim. Both were set at nine. With the slim, I could definately feel the blade more adn wound up with a couple of cuts on the side of my neck from placing the blade on the skin to hard or bad angle. I also had to do one less pass and pretty much no touch ups with the slim. How do these two compare to you?