How can i tell if its authentic?Depends if the Hellboy RDA is a clone or authentic.
They both have their ups and downs, i loved the smok but wanted a bigger device so i could eventually run the tfv8, so i traded it for the vtm150 which was big and felt weird in my hand plus button was hard to press so i traded it for the kanger kbox 200 which doesnt have all the features as the vtm150, like ramp up, but it feels a lot better in my handwell if your happy with it I would say a good trade