I. . . have come out of a tree multiple times while teaching the treestand safety portion of hunter safety. We made a video so I wouldn't need to do so any more.
I can tell you what it feels like, but I can also say I rolled out. . the stand didn't break, I didn't fall, and I had the strap adjusted as we preach, so that it is snug while I am seated. I simulated falling asleep, then out.
I could use a loss of maybe 15 pounds but am otherwise in decent shape, better I think than very many of the men my age or younger.
When I hit the end of my very short fall, the strap came up under my ribs and I cold barely breath. . immediately. I hung in a fairly face forward position and a top heavier person would easily have ended up face down.
About half the time I was able to "save myself" by getting arranged against the tree (while gasping for breath and hanging sidewise) and using the steps to get back up. The other half I had to be "saved".
Of course we did this about six feet off the ground so my partner simply got under my legs and lifted me up.
I am certain that if I had fallen any other distance, as if the stand broke, or if the strap was adjusted loose, giving me slack, I would have broken ribs in the fall.
As a display, that same buddy them falls out the same way using a **** harness, full body, then he continues on with his speech, hanging there, and turns around and using the sticks climbs back into the stand.
I hate the full body harnesses, having started out in the early 70's using none, or a rope. But you will NEVER see me in a treestand without one. A full harness with attachment near the back of my neck.
Been there, done that (many times). They are not perfect, they are getting better and better, but my continued life, health and family mean too much to me to take a chance.
CHuckC