Is one bether than the other ?
Not in my opinion it all depents on personal preference
i work whit both kydex and leater and they both have ther pross and cons .
lets start whit the pros and cons of kydex
PROS KYDEX
Kydex is a les expencive ,easier to work whit and more sturdy than leather .
needs far less maintenance and you can buy all kinds of accessories
For a kydex sheath like tek loks ferro rod holders and so on .
CONS KYDEX
because kydex is a plastic of some sort it can scratch your knife .
Also if you live in a extreme hot or cold environment your knife can freeze in the sheath if left outside.
PROS LEATHER
Leather is nice natural sheath material you can carve , tool and color to your liking.
Because leather is a softer material it wil not scratch your knife. So you can have mirror polished blade and not scratch it.
CONS LEATHER
Because leather is a natural material . you need to do some maintenance to keep it waterproof . and keep it from molting
And its more expencive and harder to work whit .
now you have some pros and cons of the twoo materials .
But in the end it all coms down to personal preference .