Yes, I tried the yoga nidra by Swami Satyananda Saraswati. You can find it in YouTube. A small 25 minute routines involving progressive muscle relaxation, little focus on the chakras, spine and some guided imagery. It will take you to a deep theta state (4-8 Hz brainwave frequency) in a short while.
If you practice meditate consistently, you may also get the experience of white light. But thats subjective and doesnt happen all the time. I did mine as a form of afternoon naps near by office - under a tree
Yes I did! Tip: if you have enough time do it after a set of Asanas and a few minutes Savasana to deepen the experience.
I had good results already the first time. It was part of the end of my first yoga class. Over time it gets easier and easier. Yoga Nidra is very relaxing for me.