I tried the sleep positioner and Lachie hated it... I now (only during the day because he is unwrapped) sleep him in his cot in a boomerang pillow and I check on him every now and then. Admittedly I would never use it at night when he goes into a deep sleep and is wrapped because he wouldn't be able to use his arms to stop himself rolling onto his tummy and possibly suffocating - but he loves it during the day because it wraps around both sides of him and it sort of elevates his shoulders and head where he lays on the top part of it.