A note of caution on the Drone. I just saw the vapor trail review of it. The drone has the same sticking fire button design problem as the Therion and Therion BF.
I bought a Therion BF, love it, but my first unit had a sticking button on day 1. The thing stuck firing at a stop light, scorched my rayon wick before I could pull the battery. My replacement has been okay, but I've since found out it is not an isolated problem.
A good friend of mine, therion just out of warranty, has the same problem.
In the you tube review the drone button stuck while Tony was doing a test vape. He mentioned it earlier, and that he had previously done an isopropyl cleaning in case there was eliquid on the button, but it still happened.
I love my therion bf, but that button is a faulty design and they keep using it.
therion stuck fire button - Google Search