The application fails to prove its point unless you pay money. – Peak - Brain Training Review

Peak appears to be a good application, but I have no way of knowing without paying for the subscription. For free users, all you have is a daily workout which means three short games… that’s it. All of these sort of applications allow you to try out at least limited features for an indefinite amount of time to see whether you like it or not, but it is impossible to logically judge the usefulness of the application itself without paying the subscription.
Review by Brayden & Pinapples on Peak - Brain Training.