Kites and wings....have used my fair share of valves and the variations over the years. My current setup on my Neil Pryde would have to be hands down the best I've used so far. This is the valve type that you see being used on other inflatable craft like SUP's. It has the centre push/twist valve in the middle. Simple to use and and reliable.
My previous PPC was fine, but a PITA as you had to screw in two parts to use, and when cold it was hard to release after a session with numb fingers.
Kites....Core, having to use that little release plastic bit. I don't know...but if flaps about if you forget to stow it and is fiddly to use.
Duotone...****. The release part (if you don't use the valve down near the wing tip) is sharp, and if not careful will (has damaged every kite I've owned), so you need to carefully replace the cap when storing your kite. They even reinforce that section where the valve touches given that issue.
Would be great to have an industry standard out there.
Other variations that are good?
Naish and NP the best I have used. PPC, Ozone, Ensis, KT all have their various issues but to be fair to them all none have ever leaked.
Definitely agree on the leak..none have ever leaked.
Valves are like the usb cords of the electrical world. Multiple adapters for all devices, then having to search for the right cord. Same as when I get to the beach, if I have a different kite/wing I need to find the right adapter. Or if someone wants to borrow your pump and they have a different brand kite/wing.
Select to expand quotejohndg said..
But that comes with strings attached!
Haha as it should 
Having been through a lot of them - my favorites are the sup style valves like FOne and Vayu use. They are probably a little heavier (negligible), can be tricky with cold hands, and occasionally I accidentally pump my wing in the deflate position like a kook - but they don't foul with sand and the pump hose seals well and allows for pretty good pressure accuracy.
Boston valves (ozone) are my least favorite. The threaded adapters make them usable, but I have nothing but frustration using them with the standard boston tip. I also find the threads get messed up easily with coarse sand and I've had them leak on me.
The "no-adapter" twist valves that attach directly to a hose are not great, but I like them more than boston. There is a convenience with not having to use an adapter, but the threads can also foul and the pressure accuracy is terrible due to lack of seal.
