The Kayfun was a revolutionary tank. Many other models are based upon the same idea.
The Kayfun lite then the Kayfun lite plus, have great airflow which is sort of a tight airflow, which produces more concentrated vape. IMO,often imitated, never duplicated. Even the Kayfun Monsters, which were sort of a backlash to companies replicating the Kayfun idea, dont have that nice tight airflow. My monsters sit in mothballs. Its because like some other tanks, in rearranging the juice flow to create more vape and widening the airflow, they lost something. That something is that nice tight full vape the Kayfun produces. Also when you do that the chances of leaking greatly increase. And like others have said, the Kayfun doesnt leak when properly assembled.
Within Kayfun production itself, you can find all kinds of different designs in different clones, which does make a difference.
I recently built a Kayfun for my kid, from collected parts that I have. He said it blew the Conqueror dual coil atomizer I sent him completely away.