This is a controversial subject.
Before anyone discounts my comments as a Provari fanboi, I will relate some facts that can be proven by testing. Nearly all of the Chinese-made VV/VW
devices use a cheaper PWM (pulse width modulation) frequency of 33 Hz. The Provari uses a more sophosticated and expensive processor that makes PWM at 800 Hz and uses better filters. Some people can experience a difference between the two, others can not. The difference in vape would be minimal but noticeable.
Now comes the subjective commentary: The Provari has only VV, no VW, but most people who choose a Provari really don't need VW. It uses a simple basic LED screen, not a fancy OLED.
People who buy a Provari choose it because it is the most predictably dependable, consistant, reliable, durable, and repairable
mod available today. Provape is a company that has a stellar track record for customer service, and will repair a Provari for as long as you own it. (None of the Chinese mods are repairable after their short warranty.) There are no bells & whistles included in a Provari, no puff counters or connections to a computer to monitor
vaping history. It just does what it is supposed to do, each and every time.