I think some of you are getting burnt or bad taste because your voltage is coming out too high. IMO voltage is what really matters for good taste and vapor production. I try to keep mine around 3.8 - 4.2 max. Once I start going much higher than 4.2 at any resistance it starts to taste bad to me. If you want to vape at a higher wattage you need to lower your ohms to get your voltage in that range.
A lot of people (including me) when they first get a VW/VV device think that now they can vape at any wattage setting on any resistance. In my experience thats not the case. Keep it in that 3.8-4.2 V range and you will get better taste. If you wanna vape at 15 watts, no problem, just bring your ohms down to .9-1.0. Just try it, you will see what I'm talking about.
Edit: I find this to hold true when using any atty, kayfun or not.