I was looking at some different E-cig's and found that there are high voltage models available such as 5v and 6v devices. Now I have an ego twist with LR cartos. Assuming 2.0ohm and vaping on 3.8v, that is 7.2 watts. Now say you are working with a 6v device with HV carto that has 5ohm. This is giving you 7.2 watts of power also. What is the difference here? Why would someone choose the high voltage device? I know the higher voltage device is going to end up giving ~.9 less amps overall. Is that the only +side?