You know.... really liking the KFC now that I have some ml's through it. Flavor is quite good actually, very condensed and concentrated.
Looking at the design, it is quite clever. It is, in a sense, a Vivi Nova coil head stuffed inside a Protank coil head.... solving the problems of each device in the process. One of the biggest gripes I had with the Vivi was the way it wicked and that whole 'tilt and swirl' thing I had to do when the juice started getting low. Both numbed the bloody blue blazes out of the flavor. And last, but not least, the damn things friggin' leaked through the center post all the g-d time (Evod and Protank more so than the Vivi).
The juice feeding system is quite well thought out.... By raising the coil and vent port higher in the chamber, you reduce the possibility of a leak if too much juice gets on the coil. That was the Protank's main issue... once juice worked its way in independent of wicking, the only place it had to go was down the center post hole on to your positive contact. And since the vent was pretty much level with the bottom of the tank, you had the whole tank pushing down on it. But on this, with the vent much higher, juice has to come in and work its way back up and down the air vent. Then they mitigate leaking even further by using a mostly sealed overflow tank at the base... leaked juice will collect in that tank and never make it back down into the center post (provided the seal around the post screw holds.)
And the evaporation chamber works rather well... You have a large chamber around that coil that narrows, which will condense the vapor... increasing its density as well as keeping it warm due to adiabatic compression effects (you squish a gas and the pressure and temp increases). Going back to the VN and PT, the evap chamber on both are SO tiny that the vapor will expand, cool and diffuse a bit before it gets to you... And, in general, hot and tight is better than cold and loose. Hey-yo!
Nice bit of engineering here.