Kahr is a great gun, thin and light. The glock is always a good bet for a reliable carry piece. Glock is thicker than the kahr series. CM or CW by kahr is more affordable than the PM series, but same reliability. If you can the best bet is to go to a range and shoot em all side by side. The m&p shield might be a good bet too, I have heard a lot of good things about them, though I am not sure they make it in a .40 cal yet.