The difference between curved panel holsters vs pancake holsters is clear on inspection.
What some call “pancake holsters’, and we call “50/50 holsters”, are designed with a body side panel and an outside panel basically mirror images, and optionally a reinforcement panel. They assemble with a seam down the center line of the pistol. Though easy to lay out and make, these can be problematic. Those with thick firearms and/or thin waists likely have more trouble. If you’ve used these, you already know they can bind on your gun, dependent on the curve and tightness of your belt.
Worth noting, some make what they call a “flat back” holster. We find that the curve produces better retention than flat, and do so without binding.
“Curved panel” holsters have a similar construction – a body side panel and an outside panel, and optional reinforcement panel. But the panels have different contours and assemble with a curve built in.
This is not the same as sewing two like pieces together and then bending the slots back. There is far less bind on the firearm, even on small waists and with thicker gun models. Since the holster is worn in it’s normal shape, holster retention is virtually the same on or off the belt. The tension of the holster does not rely on the tension on the belt. Additionally, this generally allows for a smaller outline front to back and in many cases serves to pull the grip in closer to the body.
For more on this topic, see the blog post.