Why today it is so difficult to choose a signaling for a car

Why is it so difficult to choose, in fact, a good alarm for cars? At the moment, the market in Russia is too narrow and closed. General, reliable data on double -sided car alarms, very few. Even less data written, understandable to ordinary customers language. Many market participants sometimes publish certain statistical information and research information. But statistical information is contradictory. And the study does not cause trust in consumers, as it is carried out by interested parties.