As far as VVs are concerned, I have no direct experience, but I do have a feeling it's kind of like fine tuning a race car in some respects. I think, or at the very least hope, that SI has selected their working voltage and atomizer resistances to produce optimal flavor and vapor. While that may work for most people I also recognize that everybody is different and some folks might like to fine tune things. The biggest problem I see with them, VVs, is their physical size. Yeah, I know I have a size hangup (LOL) but if things get too big I'm just not interested. An X2-650 is plenty big enough and has enough capacity to satisfy me, but maybe not the next person. Then you have the folks that like to collect things and the fans of the latest and greatest. I guess it all comes down to whatever floats your boat, but knocking one product with unsupported claims isn't acceptable and, in my mind and experience, starting someone out with a mid to large system is just plain dumb. My opinion, worth what it costs you.