As far as quality of construction, the American Derringers are high quality. But they suffer from the same problems as all derringers. They are only two shots and aren't accurate much beyond spitting distance.
I have a small Davis .32 acp derringer that I carry when I can't carry a gun. I have a CCW permit but there are times that I can not take a chance on it being noticed that I am carrying. It is so small that it just disappears in my pocket. My keys make a bigger lump.