There are a number of things that I don't like about appendix carry, inside the waistband or AIWB, not the least of which are the safety concerns. There is at least one top level trainer that strongly advocates it and all his disciples go right along with it. Let's first look at the things that I personally don't like about it then let's take look at this little experiment.
1. I think it's safe to say that the overwhelming majority of negligent discharges with handguns occur while either holstering or drawing. It happens pretty much on a daily basis across the country. Most of them are simply "training moments" that cause embarrassment but no injuries. IMNSHO, AIWB is more for the exceedingly well trained pistolero, not the beginner or even the mediocre shooter.
2. AIWB limits your movement. More for some than others but at least somewhat for anyone. Repeated or prolonged bending over would be uncomfortable, especially with a full-sized gun. Yes, I have tried it. Front snap kicks could be restricted by a gun worn AIWB, again depending on the size of the gun and the build and experience of the shooter. Many will find that even just sitting will.be uncomfortable, especially for longer periods of time.
3. Concealing a properly worn AIWB pretty much requires a closed-front garment. An open-front concealment garment will reveal the weapon every time you reach away from your firing side or when the wind blows. Generally speaking, one would need to wear an untucked shirt or sweater most of the time or a partially zipped jacket or vest.
Now, let's check out this little experiment.
The holster is not worn properly. Of all the people that I have seen wear AIWB, I have NEVER seen one worn vertically. Of course, for the experiment, that would be the safest way. Worn at the angle that most shooters do, there is also the very real possibility of launching a round somewhat laterally, possibly towards another shooter on the line or a bystander.
The shooter in a video that I saw once was demonstrating his prowess with AIWB. He said that you should step back with your firing-side leg and lean back slightly to reholster. What if that is inconvenient due to time, confined area, restraining a bad guy or some other factor? Why should I have to teach my students all these extra moves just to safely reholster the gun? During the proper, aggressive presentation of the weapon, the upper body should be bent slightly forward at the waist similar to a boxing stance to maintain balance and "get into your gun" as they say. Should one have an ND at that moment, the chances are high that you could injure the twins or even launch a round into the femoral artery of the support side leg.
The shooter in the video also has the gun outside of the pants which helps maintain just a tiny bit more distance away from the body.
He was doing everything very slowly and deliberately and carefully. In a dynamic situation where you can't be as careful and choose your position all the time, he may not be so fortunate.
Strong-side hip holster, on the other hand, has NONE of the above inadequacies and if, in the event of an ND with drawing or reholstering, the worst that would likely happen would be a crease on a butt cheek. Yes, occasionally someone runs a round down their leg but it practically never results in a serious wound. Reference Tex Grebner on YouTube and you'll see what I mean.
It can be argued that no method of carry is perfect for 100% of the people. AIWB is not for me. YMMV...