When purchasing a holster one critical factor to consider is your purpose for carrying the handgun? Are you going to open or concealed carry? Are you looking for good weapon support while taking training? Will you be mounting a light to your handgun? In any case, good holster construction from good materials will set you up for success and prevent your support equipment from getting in the way of your task.
In all three examples above, holsters made of Kydex are an excellent choice. This material is formed to the handgun providing a secure fit. My daily carry holster is molded to fit my Glock 43 and rides comfortably inside my waistband. A key feature in this holster is that the Kydex runs the length of the slide, protecting my skin from the metal. My training holster is also Kydex and is fitted to accommodate a light mounted to my Glock 19. This holster mounts outside the waistband and is secured via belt loops that are also Kydex. In both cases, my handguns are secured because of the molded shape of the holster, and they can be adjusted for tension via tightening screws. Each holster provides a stable platform so my grip to the gun is consistent every time I pull the handgun.
Kydex Holster for Glock 43 by BRHolsters