Actually, many mods use PWM. Vamo, VTR, etc. Others, DNA20-30, SX3*0, Provari and the vv3/MVP2 output a flat signal.
Some people can taste the difference between the two. I can. That's why I have two main mods, a Provari and a vv3. The only other one I'll probably get is an MVP2. For most juice, I don't like the taste change caused by 33.3 Hz PWM.
To me the PWM tastes fuzzy, if such a thing exists. Like the difference between vin ordinaire and AOC. Some really strong flavors are fine, others it drives me nuts. Given my druthers, I'll probably never buy another PWM device except as a semi-disposable.
The flat output actually boosts the voltage and it can drop it as well, below the battery. PWM actually only controls power, but it uses arithmetic circuitry to translate that to equivalent voltage relative to the resistance. You can see this in PBusardo's
reviews of various devices. Flat output is becoming the norm, but on lower end devices it's not as common.
<facetious> Of course all electronics work on magic smoke as well. If you let the magic smoke out, they stop working. That's why it's really bad if you smoke your mod. (I had to put that in there, having let the magic smoke out of many electronic devices in my life.) </facetious>
