If a motor has more Power (W) from another it means that it is better?
The short answer is no. The longer answer requires more information from you, regarding how the motor is to be used.
Since you have tagged your question with "quadcopter", I'm going to assume that you plan to put the motor on a UAV, in which case more power definitely does not mean "better".
More power (W) will draw more current (A) from the battery (meaning a larger battery and higher all-up-weight (AUW) of the craft).
You need to choose the correct motor and prop for your particular quadcopter frame. There is no one-size-fits-all motor for quadcopters. In general, you should be looking for a brushless outrunner motor with low kv, and pairing it with a slow-fly prop.
The wattage rating is usually (read the manufacturer's specs very carefully) the measure of how much power the motor can draw. It doesn't tell you anything more than that.
Wattage does not tell you whether the motor is efficient at converting the input electrical energy into output mechanical energy.
Wattage does not tell you whether the motor's power-to-weight ratio is reasonable.
Wattage does not tell you whether the motor's size is reasonable for your application.
Wattage does not tell you whether the stall torque or maximum speed is correct for the load you wish to drive.
Wattage does not tell you whether the motor's duty cycle can support the needs of your application.
If you are comparing 2 motors that differ only by their input power rating, and more power is important to you, then yes: the motor with more power will be better for you.