I suffer from tinnitus and came across this product by accident. Whilst the "white noise" element is very good, there is an underlying sound of a mother's heartbeat - presumably to help babies go off to sleep. I can only just make this sound out, but I find it very annoying simply because I can only just hear it. Strange as that may seem, I daresay other tinnitus sufferers may appreciate the problem. There is also the occasional clicking noise, a bit like the sound of a small pebble being thrown onto something hard. Very distracting (and, no, it's not coming from the player).
All in all, seeing as I had to fork out £3.99 for it, I'm not very happy.