I posted three years ago and have since used lots of these valves with zero problems.
Almost every kite I have ever owned eventually has valve problems. First with factory seals coming loose and then - if you use the kite long enough - issues with adhesive. For me, These glue-less quinko valves solve the adhesive problem
There is a distinct possibility that I am using kites way past their life expectancy.
I stopped using the little screw (that fouls the main valve threads). This screw locks the “nut“ but I have never had a nut come loose. The elastic properties of the red donut push against the nut, once tightened, preventing it from unscrewing.
So I don’t consider this a con.
No issues with hose clamps so I don’t consider this a con.
I have not noticed the weight being an issue, so I don’t consider this a con.
I was unable to come up with a no-adhesive solution for tiny struts (Sleeve opening too small to pass the rigid valve through).
I also still have to use adhesive for valves that need a bigger air flow opening.
International shipping was less of an issue on large orders - once I committed to using these valves and ordered a bunch.