Given that one has the same atomizer or cartomizer (ie. same resistance) then altering the voltage can change the wattage - the resultant power that the ecig generates. More wattage will increase vapor and throat hit and will enhance some flavors. Although some flavors are washed out with higher wattage and so you turn down the voltage to find the 'sweet spot' for the flavor you're
vaping.
It's great at sampling flavors. If you're only
vaping at one fixed wattage, then you might miss that sweet spot for that flavor. My coffee/espresso doesn't taste like much at 3.3Volts on the eGo but with the eGo upgrade PT which runs at 4.0-4.2v hooked up, the coffee/espresso comes alive. With the new vv eGo Twist the espresso tastes good at 4.8V and with gobs more vapor. On the other end, my fruit flavor - black currant - is almost tasteless at 3.6 Volts, tastes burnt at 3.7V or above, but taste great at 3.3 Volts.
I just got the vv Twist today, so I'm still testing it but so far it's all that it purports to be. So far the best setup is with the EMDCC's with the dual coils - it doesn't run hot and loads of vapor with the right flavor..... I intend to break out the older eGo mega attys and carts for this one. The extra heat at very high voltage tends to burn in the eGo
tanks.... Fine below @3.8v though - depending on the flavor. Most of my flavors are still best with the eGo-c or upgrade batt.