Earlier quoted context omitted.
Can absolutely recommend the upgrade, these stoves are far superior to PWM style "2000W or off" ones. I can even melt chocolate without a water bath on mine, they can keep temperatures as low as 55°C / 131°F steadily no problem. :D
I just have to be pedantic and say that what you are describing is the very opposite of PWM, which runs at high frequencies (e.g. 30kHz), varying the duty cycle over the tiny slice of time. The only problem with good PWM is audible harmonics, usually only children can hear them.
Which leads to the question : which ones do not have a whine? Does the breville? Or which? It’s not something any reviews I’ve seen talk about