I started out with a Vamo, then went on to a provari. The only difference is build quality and the accuracy of the voltage/wattage. The vamo is easier to use, however, as check ohm's and battery life is just a click of a button. Changing volts and from volts to wattage is also a lot easier. I checked out the Zmax and Evic, both are way too complicated in my opinion. If you're going the Zmax or Evic route, I would recommend a provari. If you just want a cheap simple mod, then the Vamo is the best choice. I would skip the Zmax or Evic; needlessly complicated, and poor build quality (cheifdiamondnipple's zmax lasted barely a week before the 510 thread was stripping)