It's fairly new and has gotten very good reviews. It's variable wattage instead of just variable voltage which means it will
automatically adjust the power level, to match your original setting, when the resistence of your atty or carto changes due to use. It has a robust 5 amp switch which does not limit what atty/carto you can use, unlike an eGo. You can use it with two different types/sizes of batteries which allows you to make it smaller, physically, if you prefer. For $40, it's a pretty good deal. Here's a review and a site that sells them:
A PBusardo Review - The Vamo - YouTube
VAMO Variable Volt/Watt APV V2
Batteries (free shipping):
Efest IMR 18350 800mAh 3.7V LiMn Battery Flat Top or Nipple Tops (2PCS)
Bottom line: models like the Vamo will provide a much more consistent vape where every inhale is the same whether the battery is freshly charged or ready to be recharged.