Apps have many issues with buggy behavior, and those same apps work fine on other phones. The phone overheats. Support from Sony is awful (my phone never received the Marshmallow upgrade). I used to have Xperia S before, and I was fairly satisfied with that phone, but this one is piece of junk. I may be forced to get a new phone soon. I'm considering Xperia XZ1, but given the experience with this phone, I am dubious that I should get another Sony. More likely, I'll quit on Sony, and move to Samsung or Huawei.
