I can only reflect on the Kicked Sabers (tho you ain't asking about those 

) but I will give it a shot anyways (please correct me)
But I am one to watch tons of videos and read everything I can when I get obsessed... lol.
The 5v Regulated simply keeps the vape at 5v throughout the battery life. 
The VariVolts allow you to ajust the voltage depending on the atomizer ohm you are using. 
The Max VV edition is 2 18650 
batteries with a VariVolt setup so you can ajust the voltage and practically never worry about charging batteries. 
Now on to the kicked versions (which are my fav personal pref). 
The kicked Sabers simply allow room for an 18650 battery and the kick module which is needed to be purchased separately. If the Kick is set at say 9 watts (and i dont know the conversions) but lets say that is 5volts just for ease of explaining...  and I screw on a 1.5 ohm atomizer it will vape at 5 volts, a 2.0 ohm atomizer it will vape at 5 volts... As you add resistance (said atomizer) the voltage will drop if you are 
vaping directly off a battery... not with a kick 
 
Now we just need a Kicked Max Edition 

 SIR LAWRENCE!!!!!!!!!!!!!!!
I hope this helped 
