After a week of using I love my ES100. I felt the build quality could have been little better for the $100 I paid (even if not metal case, better plastic case). That being said I am really impressed with the customization allowed on the app, audio clarity with LDAC, on device equalizer which works even after exiting the app. I am a scratch phobic, so I went ahead and applied 3M paint protection film which I cut to size. Since I don't have a balanced cable (waiting for AliExpress order) currently 2.5mm opening is closed so no dust can enter.