Just got my iTaste vv V3.0 a week ago. I've been sweating the voltage vs. wattage settings non-stop. I'm a techno-nerd so I'm down with Ohm's law and the associated math. So, here I am changing out atty's, checking all the volt/watt charts available online. Fidgeting with the variable air-flow of a few of my tanks. Checking those results against a couple of tanks which do not offer variable air-flow. Adjusting voltages up or down with each tank/atty/juice combination. I actually even started making my own reference chart so I knew that if I was using X tank with Y Atty with Z juice then I required X volts to produce the optimum vape. So then, being the thorough sort of dork I am, I switched to variable watts mode to commence pioneering scientific discovery once again. Certainly, I'd need more data to add to my personal reference charts. GUESS WHAT?? I'm a complete dope, that's what. It took all of 5 minutes to discover that using the variable watts mode produced the best vape regardless of atty, tank, juice, flow, etc... Set it and forget it. My most sincere hope is that I have wasted only my time; perhaps allowing you to do something more valuable with yours. Good day.