From the first night of use I have noticed a huge difference in sleep. The reason I give it 3 stars is because my snoring went from Epic with a snore score averaging about 100, to a snore score averaging around 60, and no longer epic, but still loud. I will continue to use because it is a notable improvement and the best thing that I've tried so far but still open to new technology and devices. Mouth pain is an issue but wears off in the morning after waking. Been using about 2 weeks, and today I am noticing clicking in my jaw which I don't like. I may purchase another when this wears out.