well-All I have to compare is two relatively new Spydercos and an old cheap crkt with an oval cut-out and I do not consider either Ambitious or Persistence to be "sharp" edged. Maybe I have thumbs used to years of tool use but what I would call a 'defined' edge on the spydercos is EXACTLY what I like about them. It provides just enough grip without tugging that one needs for a secure open. I can be a compulsive 'flicker' as well but both holes still seem perfect. I noticed the Persistence is a 1/16" bigger hole which curiously does not change performance r comfort afaict. The crkt-on the other hand-which has a rounded over oval works okay-but it somehow just feels-well-it feels cheap. (it probably is cheap)
