I absolutely adore my Firefly 2! I tried the original Firefly before I decided to buy the 2, and while it was excellent, the 2 is much smaller, and easier to use. I love the application for controlling the temp, as well.
Flower I bought had no THC in it. Only thing that helped my shoulder pain. Was able to use it and work, with no head high or fuzziness. I also really enjoy the flavor and smell of this strain (used in a vaporizer).