I'd go with the tobeco Kayfun clone.
I have 5 EHPRO KFL+ and have not had any issues with leaking. The TOBECO that I had did leak, so bad that I returned it. Generally the leaking is caused by the tank not being able to hold a vacuum, allowing the e-juice to flood the expansion chamber and leak out.
Second person that recommended the EHPRO, thanks. How do you make sure your tank holds a vacuum?
The easiest way is once you've put everything back together, make sure everything is screwed on tight, then use the fill screw on the bottom and bottom fill. You'll see an air bubble pop up after you put the fill screw back on and turn it back right side up.
The other way to problem solve leaks is to re-wick the cotton. Usually too much cotton is the problem, but I have under wicked my KFL before and had gurgling that way as well.
So in short, if you filled your kayfun from the bottom and are sure you screwed everything on tight, a leak will usually be caused by improper wicking.
Thought the Kayfun was the direction to go in but what about all of this that I read about leaking?