Zero,
VapourGuy. Though I've studied many in detail over a long period. What I meant earlier was that instead of having one mod that runs at 3.7 volts only, or another that runs at 5 volts only, or another that might have two settings - say, 3.7 and 6 volts, but nothing in between - the ProVari offers
dozens of voltage settings
in one PV. So it rules! And is
"like having dozens of [single-voltage-setting] mods in one."
Unless you really liked the shape/design of numerous different devices, or really
wanted to have several PV's in order to enjoy different voltages...the ProVari is
the way to go. It makes all those single-voltage-setting devices a lot less valuable than they used to be, price-wise.
Factor in all the other awesome features built-in to the ProVari, and most other PV's don't hold a candle to it. That's just my feeling...and the original poster
did ask for advice on what to get! But we're all free to hold different opinions & make our own decisions.