I have no idea how the positive reviewers find this product in any way satisfactory.
Even from a fresh start, with no other apps installed, its slow performance is maddening, you have to train yourself to wait several seconds for the screen to respond to your taps. Playing music results in constant stuttering. Forget about trying to use third-party apps.
Over time, the performance deteriorates further, to the point at which it cannot even be used as an ordinary phone: when I receive a phone call the operating system freezes, so, I must power down the phone, restart it, wait several minutes for the phone to become responsive and phone the person back. If their number was hidden (for instance, a government or council office) or not logged when they called, I cannot call them back.
I contacted Sony support and was told to re-install the system software, using their proprietary application. This took ages and, of course, wiped out all my settings. The result? Still maddeningly slow and still unable to play music without stutters.
This phone may be cheap but you will end up wasting a lot of time and stress on it before deciding to put it in a drawer and buy a phone you can actually use. Seriously, even a £15 feature phone would be able to answer calls and play simple music files. What happened to Sony? They used to be a premium brand.