Flavor is a subjective call - no way to quantify one experience as universally better, imo.
For me, the king of the flavor heap is just about any dripper; in my experience, even a cheapo AGA-x delivers a warmer, thicker, more intense flavor than the KF or any of my gennys. BUT, and it is a rather sizable posterior, the balance of flavor for the juices i prefer are better preserved in the KF. Again this is just my personal, subjective experience.
Maybe it's that my SS wick rolling skills are not up to par, or my coils aren't sitting in a sweet resistance range for my palette, or maybe it's that I feel that the air chamber in all of my gennys changes the flavor profile enough that i don't perceive them as good as the KF.
For the above reasons, and a whole host more, I will continue to experiment and try to find better atomizers. Hence my current SnP+Diver order. The same impetus drives me to jump on the Spheroid when the next batch is released. I'll probably jump on the Atomixani auto-feeding dripper when it is released as well. I have the Squape on notify, and I'd love to try out a Steam Turbine or any of the other super-high-end gennys too. My AC9 generally sits sulking - after the KF, i don't have a whole lot of reasons to revisit it.