Being DF is a NET, I wouldn't recommend sub-ohm vaping with it. Of all the juices I vape, HHV NETs require the least amount of heat to get a good vape. Since I'm not tasting his setup, I can't reliably say whether it is the juice burning or a hot spot. Some people can't taste the difference, though to most, it is plainly obvious. I have had a KF run great at .7ohms, but my experience over time has shown me that 1ohm on a mech is about as low as you would want to go. VV is a different story since most vv devices use 33Hz cycles, the temperature tends to spike on the coils more even at lower wattage. There are a lot of factors which can affect the performance of the KF. I would just chalk this one up to lack of experience and let the user work it out.