There is even the Phantom that says they will pay for your ticket if you get one using their radar jammer.
Yeah but the ticket is still on YOUR record and you'll pay for it next time you renew your insurance.
I've owned 5 different detectors, and while only one of them picked up automatic doors and such, NONE, I repeat, NONE of them would pick up all cops. Most cops now-a-days use lasers, which have a 3km range on them. By the time your "brand new, super advanced" detector picks up the cop, he's already got a ticket out and ready for you.
Any cops that still used radars were picked up by my detectors but not before it was too late. Many cops also use a trick now where they don't turn the laser/radar on until you ar close to them. BAM, you are caught before your detector finds him.
Basically the best defence against speeding tickets is not to speed. But if you insist on buying a detector, go for the higher priced ones as they are better units.
BTW - I do speed, not because my car can go fast, but because I like speed. Because of this I pay over $7000/year for insurance on my car. If you keep the speedo down you won't have any problems.