0Now a days you can't just put logic (or functionality) in your app with a normal UI and hope to make it a success. Functionality is something which everyone provides depending on app features but to make it a success, one should focus on the Ux (mind you its User experience not User design). The app should be visually appealing, the inteface should respond properly to user touch - make use of property animations and adhere to Material design guidelines. This part is mostly overlooked by programmers but to retain users when they download your app, you have to provide an easy to use app with a rich user experience.
