My hubby has no problems going to sleep -- he just didn't get any rest from it, even if he "slept" for 10-12 hours. He has been on one of those machines for over a year. He has absolutely no problems sleeping with it. The only sleep position he can't do is on his tummy....and he was never a tummy sleeper anyway. He gets a really good night of sleep, even if it's only for 6 hours some time (he normally gets 8-9)...his body isn't struggling with trying to breathe through the night so he's rested when he wakes in the morning. His sleep is deeper and he now has more REM time. Plus, he doesn't stop breathing in the middle of the night anymore. (on his sleep test, he stopped breathing 78 times). We just came back from a 3-week vacation in Europe and he didn't take the machine with him. He was constantly tired; his sleep was so shallow that he'd wake up about 5-7 times a night...he had no real appreciation for the benefits of that machine until he quit using it for a while.