I have not tried them all yet but the sleeping one definitely worked. I did not experience the same results with the study and focus ones perhaps it is because I did not listen to them long enough.
A few suggestions and necessary additions:
Please add a way to have ones personal library of binaural and Isochronic sounds. The selection within is simply not enough.
Make the download of mixes optional. It is annoying each time the app starts to be prompted to download the mixes. Besides, I hate them, I do not like them so I do not understand the must in there.
An iPad version is very much necessary. Please make an iPad version of the app or even better make it universal.
Have the app work with bluetooth and earbuds with remotes to stop and start the sounds.
Add the ability to combine binaural sounds: Focus+Study, Break+ Creativity, Sleep+Break, etc.
If all of these are considered I will gladly update my rating to 5 stars.
Ali46712001 about Brain Upgrade Premium - Improve Concentration and Relieve Stress