Yes, i ordered directly from Janty, and yes, every Janty Ego VV is a USB passthrough.
I don't use it as a PT on a PC hub, though, i always charge them via a USB loader.
As far as what i can tell there's somewhat of a little "cave-in" when the battery comes to the end of the charge, but IMO very shortly before the battery itself goes into "charge me now, fool!"-shutdown.
I didn't test the voltage levels with a multimeter, but from what practical test i can tell they are as good as a regular JT battery, BUT:
Sometimes the "level" resets during vaping, for some time after the battery has been taken from the charger, but then you just have to "gear" up, when the charge is not full to the brink the preset memory seems to work well.
Yes, i can tell a definite difference between the voltage levels as i use the VV with the big, "stove-pipe" Janty EDC cartos that are XXL and hold a whopping 5ml.
LED goes:
Red (low): Meh, more like an Ego-T. Not stunning, but ok.
Violet/Purple (mid): Wow, that's a good amount of vapor, the flavour is even tastier now!
Blue (high): Wow, massive amount of vapor, but the taste sensation starts to diminish now.
I prefer the mid-level, because it doesn't drain the battery that fast and gets the optimum out of the cartos i use. I thought about using an Ego-T atty, but i recently killed one by going blue testwise and pushing the limit...
ATM i use either normal Ego-T batteries(650 mAh) or the VVs, but i'm thinking of getting a E-Power ("King Kong") mod, because variable voltage mods are either sloppily produced (Lavatube) or outrageous in price(ProVari) and the VV fits my needs perfectly because i don't see it as a ProVari or such.
To me it's just an Ego battery with 900mAh and the option to use three settings going from "light fog" to "London in autumn"-amount of vapor and the possibility to use it as a PT if need be.
But: I'm going by the 17,99€ (that's ATM about 23,60$) that i paid for one EgoVV including USB cable.
31$ for one EgoVV is, IMO a bit high.
My thoughts, buying the EgoVVs was that a Joyetech Ego PT battery of about similar size (900 mAh) goes for about 18-19 Euro here, but lacks the variable option.
The EgoVV has a variable switch, but sadlily not an on/off-switch or a 5-click-shutoff.
I've seen quite some remarks from German EgoVV users having complaints about their VVs and refunds because some/many "didn't work", but i can't say if those were MDU-related problems or if the customers just received faulty products.
The EgoVV is a nice and good PT 900 mAh battery and i'm fine with the drawbacks it has and i see it, regarding the price in Germany/Europe as a replacement for a regular Ego battery of the same quantity (900 mAh).
But a Lavatube or a ProVari it is not.