There are plenty of good holster makers. Personally, I like Tenicor, Phlster, KSG Armory, and JM Custom Kydex because they each make holsters that have features that work well for me. There are others that make similar holsters, but I’m never sure if they do the small things like polish their edges well, which makes me hesitant to branch out when I need a new holster.
Since so many people talk about the built in wedge from Tenicor, I’ll add my experience. I bought a Sagax Lux that has one. I don’t like the built in wedge. It’s made for what they believe the “average” person needs. For me (5’9” 200lbs), the wedge does not do a good job preventing printing. It cants the grip of the gun into my body well, but causes the red dot to print even worse than it does without a wedge. If I didn’t have an optic on my gun, it would work well though.
Because built in wedges are built with certain assumptions that may or may not hold true for my circumstance (body type, gun configuration, carry location, etc), I prefer holsters that leave the back flat so that shape my own wedge out of yoga block and attach it via Velcro, if I determine I need one. If my weight fluctuates and I begin printing with the wedge I made, I can shave it down or make a new one and use it on the same holster. That’s my preference for a wedge and why.
Another feature I like in a holster is for it to be ambidextrous by allowing the hardware to be removed and placed on the other side to switch between left and right hand configurations. That way, if I break my arm or something like that down the line and am in a cast, I can have a family member assist me in switching over the holster to be carried for drawing with my support hand while I heal. It’s not a huge concern of mine, but there are a lot of really good holsters (Phlster, KSG Armory, etc) that allow for this at no additional cost that have all the other features I want, so it’s a small differentiating factor when I go to make a purchase.