The main criticism is simply the volume that can be controlled to very loud only by loud. But well, the volume is also necessary to drown out to the seemingly quite inferior electric motor (that is, without music still ists too loud).
In addition, the music will change by continually and starts there where they left off, making it as solid bedtime also not really good for. (We personally liked the choice of music is not).
The only thing that we really liked were the butterflies that could project them on ceilings and walls, but unfortunately it was because of the loud Motos not also useful for this.