I bought this to replace a different machine I had for over ten years - it had a variety of sounds on it like rain,brook etc. I would run it on continuous but after ninety minutes the sound would fade to nothing with a long silent break and then it would start suddenly at high volume on the next ninety minute cycle which was waking me every time. The electrofan is a steady continuous sound with no fluctuations to disrupt your sleep and it has helped drown out inconsiderate neighbours downstairs banging cupboards, drawers etc.
It is so simple to use I can alter the volume in total darkness and it does not have any annoying lights which you don't need when trying to sleep. I am very happy I bought it.