Tom, it's not total magic, but close to it and it. Often it will save the day when you think you have no phone service. And, it improves your mobile hot spot for the internet.
Last month with Setters in the Smokies, we had no phone signal. The Speedboost worked in both our campers and we were also able to make a mobile hot spot with our phones because of it. Without it, no dice.
I had forgotten the metal ground plane for the magnetic mount antenna so we improvised by sticking the antenna to the bottom of a cast iron skillet and then put it on the roof. 