Class A operation is the transistors are fully biased (turned on) meaning there is no crossover distortion (notch??) when the signal swings from + to - and vice versa.
A watt is a watt, so Class A watts are not more powerful than say Class AB watts.
Of course, the drawback of Class A is heat and energy consumption. The amp must dissipate all of it's power whenever it is turned on whether playing music or not. Either the energy goes out the heatsinks as heat, or to the speakers as electrical energy, or a combination of both in most cases.
A watt is a watt, so Class A watts are not more powerful than say Class AB watts.
Of course, the drawback of Class A is heat and energy consumption. The amp must dissipate all of it's power whenever it is turned on whether playing music or not. Either the energy goes out the heatsinks as heat, or to the speakers as electrical energy, or a combination of both in most cases.