depends on a lot of things. power handling for each driver is not one of them.
vehicle type, enclosure type, Xmax and cone area for the subs, etc.
Theoretically, the output between both options shoule be equal, since going from one sub to two adds +3dB, and double the power to one sub is +3dB, you're gaining the same thing by using two subs with double the power, or 4 subs but with half the power to each. In reality, they won't be equal, but the difference won't be very significant.