Honestly, I don't understand all the excitement about this model (Vapor King). I managed to get a kit about a month ago (with two batteries). I've used both batteries with carts. The flavor is good, but the vapor isn't the best. You have to take very long drags to get good vapor out of them. The e-cig style E9 is much better.
The Vapor King cartridges are almost identical to the newer cartridges for the e-cig E9 (aka Red Dragon, Bloog, Smoke51, etc). I am not speaking of the crappy cartridges from e-cig or Red Dragon that come 4 in a pack, but the newer ones that come 5 in a pack like available from Smoke51. The threads are not as deep on the VK carts, but are only slightly different.
If you compare the E-cig E9 (same concept disposable atomizer with cartridge) to the Vapor King, the E9 beats it hands-down. I've ordered a bunch of cartridges for the Vapor King from two different suppliers. I just pop them on both my Red Dragon and e-cig E9 batteries, or my U9 USB Passthrough, and the vapor production is MUCH BETTER. The threads don't match exactly but 98% of the Vapor King cartridges screw onto the E-Cig and work fine. They just don't screw all the way down. Occasionally I'll find a Vapor King compatible cartridge that doesn't fit on the Vapor King, but almost all of them do. The occasional odd-ball Vapor King cartridge that doesn't fit, is in a pack of 5 and amongst those that do fit. In another post LEAFORD noted that he couldn't get the Vapor King cart on an E-9 style. I believe him, as I say I encounter a very small number that don't fit either. However I've smoked at least 100 Vapor King cartridges on my E9s. Regardless, the newer style E-Cig compatible cartridges are almost identical to the Vapor King.
I've been smoking 8 cartridges a day for the last month, mixing and matching the Vapor King cartridridges with the E9 (aka, Red Dragon, Smoke51, Bloog, etc), and the E9 style batteries always work much better.
Beware, though. The E9 style cartridges don't fit on the vapor king. That's why I usually end up buying Vapor King Carts... they fit on the VK perfectly, and pretty well on the e-cig E9 style. I can use either type of batteries, but I only use the VK when my other batteries are dead, because they just don't produce the same amount of vapor.
I only own 2x Vapor King batteries, but i own a lot of the e-cig type: 6x e-cig E9 batteries, 2x U9 e-cig USB pass-throughs, and 2x Red Dragon Batteries. Unless both of my Vapor King batteries are odd-balls, the e-cig E9 is much better. Has anyone else owned and compared these two models and smoked the Vapor King carts on the E9?