We bought one for our little man. In fact i was so convinced we had to have it that I went out & got it regardless of the fact that dh was questioning it from the start.
All I can say is I personally did have peace of mind when Ethan slept on it but we have taken it off his bed when he was about 5mths old because it was causing almost a sweat effect & often I'd get him out of bed smelling damp at the back of his head.. this went on for a while then i realised it was probably the darn plastic wrap around the mattress..so off it went.. I'm not sure what it was supposed to do be honest but it certainly did contradict everything we had been told to date about only ever using natural fibres to sleep baby on etc.. Others swear by it but I have noticed a marked improvement in ethans sleep since we took it off & there isn't that manky smell anymore either