I was all hot to buy one of these after seeing all the glowing reviews. Before I bought it I checked out a thread on the forum about the eGo One. First pages: praise and adulation. Later pages: wailing and gnashing of teeth. Flooding, premature coil death. Some people happy, some not so much. No problems with the batts, just the tanks. I don't know if it is a design issue or quality control, or both, but I decided to pass on the tank. I don't like tanks with little slits to see the juice level anyway. I bought the battery any how and put my eLeaf GS Air MS on it. Works so good I sold my iStick 20w. Nice looking, too, if you like 'em short and stubby.