Since 6 months of use ... just plain annoying ...

I bought this phone for professional reasons. According to several tests and reviews, it is currently to be the "best" dual sim mobile phone, the selection is quite manageable. If this phone is supposed to be the best, I wonder if the other phones in general have basic functions, because even the phone rarely works with this phone.

For each positive and negative points:
+ DualSim, work (though not simultaneously) and is easy to use (simple switch)
+ Battery lasts normally long charging time is fast: about 2 hours, then it is full again.
+ Boot time is normal despite DualSim

- Light sensor: the there is simply not .. In concrete terms, the shadow visit in sunlight to the button to see the display brightness to turn to maximum.
- Voice Quality: I'm often asked whether I have switched the phone to speaker because I am so poorly understood. I hear my opponent always very tinny and distorted. That's why I only phone with Bluetooth headset in order to understand at least everything.
- Bluetooth: My headset has always served us well in this phone, however it breaks in the middle of the talks spontaneously and have to reconnect after a few seconds. I have subsequently tried with other phones where the error did not exist. The error is quite unpleasant if you do not a few seconds several times in an interview long distance.
- Power: The phone hanging constantly, although I hardly installed apps. Concrete example: The lock screen turns off again before the phone has processed that I've unlocked it. That's why you need before several attempts to unlock it.
- Touch sensor: Often wiping gestures are not recognized. Sounds less tragic than it is, because if you scroll through the screens to activate spontaneously 2-3 apps, what a long wait for results in (see previous point)
- Connection: The antenna is very weak, I have had with my old phone 3 units, with this I often do not receive.
- Connection stability: the compounds are occasionally separated spontaneously.
- Call: Even calling the call list takes a good 10 seconds What can be very annoying (especially if you count the Entsperrversuche)
- Apps: falls often on, so I just almost all deleted.
- Restart is often required
- Sometimes the phone rings, but can not handle the lifting. Then it rings loudly and incessantly, until you remove the battery and it restarts. Unpleasant for the environment, the caller and the callee.

All these errors occur not only in the way my phone on, but can be found in many forums, I have unfortunately failed before buying.
I have now spent a long time trying to make the phone reasonably usable, but all attempts have not helped. Since I am unfortunately outside the return period, I have to keep it now. Maybe there is a reserve telephone or I give it, because I really can not use it.

Clearly: not advise!