You can control the DRV8825 to reduce the current when you don't need it. Sometimes you can get away with totally de-powering the stepper, using the reset pin.
If the motors have about the same output power then they will have about the same input power. Even though the voltages and currents are different. The DRV8825 acts like a DC-DC converter and is highly efficient. Power input is very close to power output. It will convert the input voltage to the voltage that the stepper needs to make that power.
Given a choice, I would pick the one with the lower nominal voltage. That lets you drive it "harder" to make each step. The difference will only be noticeable at higher speed.