I do not have direct experience with Zerona but believing from my reading that CoolSculpting is more effective, I have performed the treatment in many patients. The down time is minimal. Some patients bruise temporarily and some have soreness and tenderness and even tingling but this doesn't have to preclude someone from exercising the next day!!! But if you want to wear something revealing, there can be up to two weeks, or even a few days more, of a bruise occasionally from CoolSculpting.
Web reference: http://www.thenyac.com/zeltiq/index.html