I just had a second sleep study Friday night. The first sleep study was better than the last one. I do not feel like I slept at all. I was still sleepy when I left. I also like to sleep on my stomach, since you have all the wires and mask on I could not get comfortable enough to sleep. I know I did sleep here and there. I have used both the nose pillow and the full mask. I like the full mask better. It is all up to you. You can get up to two mask a year, so if I was you I would try both and then you can decide on your own. I went with what the medical guy that came to the house to se