I love my Scrappers but I have found they(and every other knife) usually need some work before I am happy with the edge. I use a Lansky which is a bit different.
For my SS4 I made the edge a very thin convex edge that goes from 25 to 20 to 17 degrees. It would be to thin for most knives but infi can handle it. My Mutt came with a 25 degree edge that was very well done and consistent. I think I may reprofile it to 20 but 25 is a decent enough edge for hard use.