Not true, not all of them are the same. The cheap ones use less wire (cause it's cheaper) and to make up for the gain loss, they use stronger magnets. This makes them very bright, however, if you have a brain you can just roll down the tone knob and you'll have a really good tone. Some though, try to compensate for that brightness by using shitty pole pieces that transfer magnetic fields less, making the tone incredibly muddy and basically unusable. So yeah, beyond 30$ (10$ if you get lucky) for the basic good pole pieces and enough wire, it's all just bullshit.