The three parts
Every booster is the same three things: an external antenna that picks up the existing signal, an amplifier, and an internal antenna that re-broadcasts it inside. That is it.
Because the external antenna is the input to the whole system, where it goes and where it points matters more than which brand is on the box. A well-mounted mid-range kit will beat an expensive one bolted somewhere convenient.
When a booster cannot help
If there is genuinely no signal reaching the property at all — not weak, but absent — a booster has nothing to amplify and will not work. Any installer who sells you one anyway has not done a survey.
The better answer in that case is WiFi calling over whatever internet you have, satellite included. Every modern phone supports it and it works where cellular does not.
Why DIY installs fail
The most common fault we are called out to is oscillation. If the inside and outside antennas are too close, or not separated by enough building material, the booster hears its own output, detects the feedback loop and shuts itself down to avoid interfering with the carrier network.
It is not a faulty unit and replacing it will not help. It is a mounting problem, and the fix is distance and separation between the two ends.
Steel buildings
A steel-clad shop is one of the clearest cases for a booster, because the cladding is exactly what is blocking the signal. The external antenna goes on the outside where signal exists, the internal one goes inside, and the metal skin stops being the problem.
This is also why phones work standing in the yard and not ten feet inside the door, which is the thing that prompts most of these calls.