Update:
- cellular connection breaks up every two minutes for about 10-15 seconds.
- iPhone usually shows that wi-fi is connected, but when you actually wanted to use it, like safari, mail, navigator, app store, it disappears right away. It took me 25 minutes (and about the same amount of tries) to buy 3Mb app using 7Mb/s home wifi connection.
- location services are not very accurate (comparison to what I had on iOS 5.1.1.)
- battery is dying like crazy. The device can shut down even it has more than 40% of battery!
- and as I've already said before - Text Messaging and iMessage is not working, even-though it shows that it is activated. And again - I can not rebot the device - this way I will lose unlock function and to every bad aspect I described above I will even lose the call function.
P.S.: right now I don't want to rely on the device, so I use cheap old LG as a phone, and iPhone only to watch videos and listen to music while I'm out.
Sucks...