The punch mode is based on the Normal mode (so not on the classical one).
In my experience it works fine and gives a subtle extra saturation if asked for. But if you do not have many rich colors in your image, the clarity tool cannot do much about that of course. I never got overcooked images, but it all depends on what you did *before* using the clarity tool. If you changed the saturation already in some other tools, like in the color wheel or within the exposure tab, you indeed might get too much saturation or even overcooked images. But that then has nothing to do with the clarity tool itself.
Hope this helps.