brushless vs brushed motor
You have calculated the brushed motor's input power using Power(W) = Voltage(V) X Current(A). You can calculate the output power using Power(W) = T(Nm) X RPM X 2Pi/60. Output power is equal to input power minus losses. For estimation, you can assume output power equals input power or assume losses are 15% or so for a better estimate.

If you are comparing two motors for use with the same gearbox, you need the motors to have about about the same torque for full speed and rated power. Just matching the power ratings is not enough.


  I have seen people say brushless is more powerful etc...


There may be some truth to that, but it doesn't mean much without numbers. If the output ratings are the same, one is not more powerful than the other. However you may find that a brushless motor is more efficient, smaller and lighter than a brushed motor with the same speed and torque rating.