I happen to have one. It performs well so far, for a 3.7v/5v/6v/6.4v
device. I have had mine for 2 months. It comes with several inserts for different atomizers, but I only use the 510. I bought the Ultimate Indulgence kit that comes with all the accessories from :
Ultimate Indulgence 6V Kit (Titanium) [VJK006] - $104.95 : VaporJunction, E-Cigarette Supply Use ecf10 for 10% off.
I can use it as a 6.4v device, it came with 2 x 3.2v LifePO batteries and the extended tube, but I found that all my juices tasted burnt at that voltage. Maybe different juice would help. So instead, I use a 18650 battery (not included) for a longer period between recharging. The pass through works very well at 5v (or very close) when I feel like higher than 3.7v
vaping. All in all, I am pleased with it. I did wait and read other peoples impressions, as well, before I purchased. I have learned the value of 'look before you leap'. Good luck and happy
vaping.