I use to buy leather holsters for all my guns. Then I discovered kydex. I like the kydex much better.
By far my favorite OWB holster is my Raven Concealment Phantom (Kydex)for my G26/G19/G17. This holster can also be converted to an IWB, and it works well in that posisiton. The only negative is I had to wait 20 weeks to get it. Raven also has excellent customer service. I made a boo-boo trying to modify it to accept my G34 and ended up messing the holster up. I called them and they told me to send it in and they would take care of it at no charge. I decided to research kydex a bit more. Made a make shift kydex press and fixed it myself. Raven now has an express line of holsters for Glocks and 1911s so you dont have to wait as long to get them.
Shortly after falling in love with the Raven, I ordered a similar kydex holster from Double Tap holsters for my Sig P226. It arrived three weeks after my order. The problem with this holster was that it didn't fit my 226. It didn't fit my 228, a friends 226, and a 229 either. I contacted Double Tap and told them about the issue. They said to send it back and they would look at it. I pondered on it a while and decided I felt confident enough with kydex that I would try remoulding it myself. I had just acquired a Walther PPQ and needed a holster, so the Double Tap holster got moulded to my PPQ. It turned out great.
I have also been evaluating a few of the hybrid style (crossbreed/white hat) holsters. These holsters have a leather flap backing with a single layer of kydex moulded to the shape of the gun. They are IWB rigs designed for concealment. The first one I got was a Galco Kingtuk for my Glocks. It is a nice holster and conceals well. I dont think they use kydex, but a similar plastic. The only issue I have with the Kingtuk is that the back side of the leather (part that touches the body) is very smooth (flesh in). It likes to slide down, especially if it is resting on a tucked t shirt. It would be better if it had a soft "Grippy" material applied to the back. Maybe like the foam rubber material found in the bottom of stand up tool box drawers. I dont think that would irritate the skin, but I am unsure if it would be durable enough to last.
I just received a White Hat holsters Maxtuck. What I like about the White Hat is that the kydex portion is exchangeable. Say you have two different guns and your wanting a Maxtuck for both. All you need is a complete holster for pistol A and a kydex section moulded for pistol B. Saves money. I havent had enough time with this holster just yet to give it my blessing, but I have some opinions on it. It appears that White Hat uses a standard pattern on their leather backing for all their holsters. Not a big deal because most pistols have the same general outline. Of course the kydex is moulded to the pistol of your choice and then attached to the leather backing. Just from my short time with this holster, It doesnt appear that they test their holsters with the guns after they are assembled. When I put my pistol into the holster, there was leather and kydex in the way of getting a secure grip on the pistol.
Not a huge deal because i fixed it by removing material with a exacto knife. One thing about the White Hat that looks promising is the flesh of the leather is whats against your body. I think this may help keep the holster from slipping. I may post a better eval later once I get more time with it.
I have been experimenting making my own kydex holsters. I made one Raven style for my Girlfriend's G19. It is about 95% complete at this time. My next project is going to be making a hydrid holster.
I hope this helps.