To boost or not to boost...that is the question.

A booster does not give the brakes more power in itself it just makes the pedal effort less. Now a booster could give a person more braking power because they may not have the strength to push the manual brake hard enough to achieve the same amount of line pressure as the boost assist vehicle so in this case the manual brake vehicle wouldn't have as much stopping power. But as Dusterb318 mentioned it is the bore size of the master cylinder that changes the braking power and effort. Piston sizing of the caliper or wheel cylinder will also change braking power.

Chuck