I haven't had SP in a while, not too many times since last winter. But it does tend to occur more frequently when I'm dead tired and trying to catch a nap.
I find this shit very interesting, although i feel like I'm on the verge of death nearly every time it occurs.
I had an experience that I rose and was levitating over my own body, which after enforced the whole idea as your body being just a vessel. It's difficult to explain the view to others who haven't had something like this occur, as it was almost a combination of 3rd person and 1st person view simultaneously.
I think that was the only positve experience I've gathered from SP. Similar shit has happened though when this nigga burned me up on some laced. However it felt like my soul was just floating within my body, and never actually transcended.
I try to experiment with SP/Meditation/OOBE's as they are all in some way connected, but some of that shit is od haunting. I can't explain the overwhelming vibration sound (may be electric current passing through the body)... but I think all the visuals of demons and other crazed shit are just manifestations of my subconscious.