The first thing that comes to mind for me is having that strap at neck level.
I hear it rub my jacket collar or hat when I turn my head.
If I'm standing and facing the tree it is often in my way, especially when looking around the tree.
It has gotten in my way in the heat of the moment when I had to swing and draw quickly.
I've often wandered what the outcome would be if you had that strap under your chin because you turned to look at something quickly without ducking under the strap......and that's the point you happen to fall. Seems like a good way to snap your neck.
Overall I find the entire harness mildly restrictive. I think about it and it's discomfort. I don't want to think about things when I'm hunting. I want to eliminate all
distractions if possible.
The twisting an falling is entirely dependent on if you are facing the tree or away from the tree. 50/50 for me.
If you do end up suspended from the back of your neck, it is not easy to get yourself pulled back up. I've practiced it. Not fun. If you fell from a climber I'm not sure most people could self rescue from a full body harness.
Constriction sets in quickly on your groin, then loss of feeling and strength, then panic....not good.
Pressure from a RC harness is entirely on the back of your hips and you can kick away from the tree. You can hang there relaxed and gather your thoughts to get yourself back in the stand.
There are a few videos on Youtube about guys practicing falling with an RC harness.
Another advantage that I foresee, but haven't realized yet is the ability to lean into the harness to steady for a shot. You tie in at waist level and that gives you another point of contact for steadiness, position awareness, and safety.
I may find out I'm totally wrong, but it seems that everyone who makes the switch stays with the RC harness.