My guess is that most people who carry a gun regularly have a holster box. That is because holsters are intensely personal and they are also a solid “impulse buy.” Something catches your eye and you drop some cash. Before you know it, you have a holster box.
No matter what you use to carry your gun, at the end of a long day, you will likely notice you have a gun. The best way to test a holster is to put it on wear it till you notice it, then decide if you can live with it. After a while you will start wondering if another holster wouldn't be better and you will go through the sequence again. Soon you will find something that is just right for you.
So, what makes a good holster into your favorite holster? Comfort is the most important element. If the holster is not comfortable right from the start you won’t wear it long and then you will get to the point where you don’t put it on every time you leave the house. That’s no good.
Next up is concealment. It should be hidden. Concealment is the goal, no one needs to knows you have a gun and that's way it should be.
Security should be next. You want you gun to stay in place. If you're an active person, you don’t need a gun flopping around or worse yet, falling out when out or helping a neighbor move.
There are a lot of product out there, they all work. Some are better than others. You can ask around, however, it's really for you to decide– and that’s half the fun of starting a holster box.