Mainly linearity, efficiency, gain, flatness and other indicators
In other words, the grid voltage of the high quality power amplifier is very important, the larger the grid voltage, the larger the static current, the linearity of the power amplifier will be better, but these are not absolute, the grid voltage determines the power amplifier is A, B or AB class.
In the case of Doherty amplifiers, the power ratio is very important and has a great impact.