The UX UI of the app is very good. Controller frels very good and buttons are good. The Build quality of the controller is very good and feels good with the phone. However, if I were to critique one part is that it can feel a little loose both with the phone and without. This is understandble because of the midsection, however, the quality of the controller would improve if the middel of the controller felt stronger this part could be more durable. I'm afraid this could get looser over some time. All in all, the controller is very good and does its Jon very very. Thank you.