The EM7-10 has been designed to power speakers like the B&W where more power is required. Push-pull amps, when properly designed have lower distortion and are preferred when several watts of power are required. As to noise, I will never make a noisy amplifier. In a properly designed amplifier the noise can be very low regardless of the output configuration. One needs to have some standards (NUMBERS) for noise. There are amplifier makers who feel 2 mV hum is reasonable. My limit is about 12 dB below that (0.5 mv). I would be embarrassed to release an amplifier with 2 mV of hum.
Although it is true that push-pull amplifiers cancel power supply noise they do not cancel the hum modulation that occurs as the signal swings from one tube to the other. When I was teaching my guitar amp class a student brought in an older tube Fender amp. Although the hum was canceled in pp when we reduced the B+ ripple the sound improved markedly. Many years ago when I was consulting for Seymour Duncan I learned that the "hum null" adjustment in guitar amps was setup to balance the idling current (bias) of the output tubes and thus cancel the supply ripple , but not the hum modulation. In Hi Fi amps the hum pot is to balance out filament hum. These ideas are as different as night and day.
