3 way pan tilt heads allow you to move one axis at a time, a ball head allows free movement when the ball is unlocked and although it is faster to use, it is difficult to adjust. Typically, I use ball heads on monopods and 3-way heads on tripods. Some ball heads has a separate pan, so that you can pan without affecting the angle.
I will not recommend ball heads if you are shooting architectural where it is important to obtain a levelling.