You know, I had same questions as you. Then a few weeks ago, in desperation because I ran out of my percocets and was SICK, I used ice for the first( and last) time.
Granted, the effects could have been tainted because of the opiate withdrawal but overall I did not enjoy the experience. I have friends who LOVE it. And sadly those people are often addicted and eventually lose almost everything they have in the pursuit of ice and the high.
I did get an immediate rush. Could not stop talking, could not sit still etc. Then after a couple of hours I felt nervous and jittery. Well there was no way I could sleep, and I really tried. I ended staying awake for about 48 hours.
When the high was fading I began to feel very depressed, hopeless and very guilty for using ice in the first place. I was exhausted and could not rest. I did not want to eat, my mouth was dry and I began to feel like I was never gonna be the same again.
After I FINALLY got some rest I was sore all over, like I had been running a marathon, and also found that I was keeping my jaws clinched involuntarily and my teeth ached.
Like I said, everyone has their own experience....but it was not something I care to EVER try again.