I've had both the Jack and Sensor 4 batwing. When having some roof work done had the Jack installed. One thing I didn't really like was how far up it sticks up above the roof (installed on a 5er). That concern became reality when it was knocked off from a small branch going into a State Park last fall, so installed the Sensor 4. Having used both, I've felt their performance is about the same. What I found out when the Jack was knocked off is it's built kind of flimsy inside which you don't see. If I someday would use a Jack, I would install the head replacement only.