I have never owned one because I have never tested one that felt good to me. My fear is that if I loosen the head and forget to hold the camera with my other hand, that the camera will crash down into a different position possibly causing damage. I am sure it is something that you just get used to. There are also pistol grip ball heads that are a bit lighter and less expensive but they tend to seem a little too light for a larger camera and lens. These pistol grip heads seem more suited to 35mm cameras but I have seen photographers using them for medium format.
Tripod heads are in great supply.
I suggest that you try out many different heads prior to making a decision. Since it is the part of the tripod that you will be using the most, you need to feel quite comfortable with it. Take your time and select the one that feels best to you. Be sure to test its range of movement. You don't want a head that will not let you point your camera reasonably high or reasonably low.