@eos;
The N82 tactical holster I have for my S&W Shield is the Original, which has a neoprene(?) holster; think soft side, so the moment you draw your weapon, it collapses. This makes re-holstering impossible without either pulling the entire holster out of your pants or trying to hold the mouth of the holster open while you try to re-holster. Of course if you attempt the latter, you cover your weak hand with the muzzle of your gun every time, which is not ideal.
So, for EDC it serves very well (I don't draw my weapon for any reason during the course of a normal day). However, for instruction, when I usually have to draw and re-holster a hundred times I needed something with either a hard kydex-type shell or a hard leather holster that would stay open after a draw.
N82 Tactical does make a kydex holster (called the Professional), but I didn't get one yet for my Shield. It would've taken a week or two to get one ordered, and the class was in a few days so I just went to the LGS and bought a Kingtuk for the class.