造反 = rebellion, always serious. 逆反 = rebellious [nature], may not be as serious at all; an adverse reactionary action opposite to what is applied.

造反 - is more of an action. When we yell at a teenager "你要造反啊", usually we are trying to accuse them for outrages behavior. And also it can be used to describe the actual revolutionary activities in an informal way. 逆反 - is a description of attitude. It is often seen in expression "逆反心理", describing a phycological status.