I received a Z1 as a recent upgrade from Vodafone. All aspects of the phone were amazing although I wish Sony could do better in terms of the software design like Samsung does. After a few light usage of the phone, I started having serious issues with the WIFI. I tested the WiFi with all the applications closed, bluetooth and NFC disabled, and the same problem remained. I event tried three different routers on channels 1-11 (apparently Sony xperia models don't pick up channels 12 and 13 !) with all the security measures disabled. still no luck.
The main problem was the very weak wifi signal, where other phones including Iphone 4S and Samsung note 2 both operated normally at the same time. (I didn't just rely on the wifi bars, as it is highly dependant on the software desing and how sony calibrated those bars against the signal strength). So I tested it with different apps including Wifi analyzer. Sony Z1 keeps on dropping the wifi when the signal goes lower than 1 bar. I left the phone downloading a few files whilst moving around to the furthest distance (about 6 meters away). including at home and other locations with strong wifi signals.
So to cut the long story short, I returned the phone and I got a sony z ultra instead, the same problem exists, although Z ultra seems to have a slightly better wifi. So I checked the hardware architecture of both phones and I realised that his problem solely lies with the software and the fact that both xperia phones have some internal software components trying to minimize the wifi energy consumption.
Other than that, bluetooth connections to SBH52 keeps dropping from time to time, and the bluetooth bandwidth is lowered, which causes the sound to get distorted for a few seconds (especially when smart watch 2 is connected and notifications updates are sent to the watch).
I have decided to return the z ultra too and ask for samsung note 3 instead. As much as I loved both phones' design and accessories, but these are serious issues for a tech savvy like me.
