I like my leather and my kydex. I like the leather cause it an iwb. And its the first one I bought. I like my kydex cause its light weight. And durable. I'm getting ready to buy a cross breed and have the best of both worlds.
I like leather for daily carry because it is more comfortable, but I prefer kydex for carry in the field because it will stand up to water better. By “in the field” I mean out hiking, camping, fishing, hunting, etc. when you are in the woods or mountains and may have a close encounter of the wet kind.
Kydex paddle for me, It doesn't stretch, good retention, easy to remove. I like leather but during the summer months it can get sweat soaked and stinky.
I use leather mainly because I just like the material. The look, smell, & feel. But, my brother has a kydex & it seems ok. I dunno, I might in the future, but I am happy for now. My mag holders are kydek though. They aren't bad, & and do remove easy enough, but I still prefer leather.
I prefer Fobus for carry and for IWB I carry a Glock 23 in a M-Tac Minitour holster IWB . This holster will completely conceal a pistol and you can tuck your T-shirt over it and nothing will show. After a while its like carrying a wallet, very comfortable. Go to COMP-Tac.com to view this holster. NRA Instructor
I use both, but prefer kydex .... cheaper. indestructible. perfect fit from new, no break-in involved. tons of paddle models available, which I prefer.