Hi guys. Just found this thread and thought I'd post up my experience... It's been a love hate thing...
Got my first Z3 on 1 Dec 2014... Loved the battery life and the phone in general. But on 27 Dec the darn thing just died, while I was away on holiday. Great!
Finally got to the Allandale repair centre on 5 Jan. Next day was advised I can get a new device at the store I took the contract at. Problem was that mtn had no stock country-wide. Anyway, i put up a fuss and eventually a few days later, someone managed to find me one at the head office... Switched it on and all seems great.
Loving the phone despite the first one dying. I get two full days of pretty heavy usage which is fantastic. My previous Samsung S4 mini used to last from 8am-7pm before dying... So that gives you an indication of battery life. Apparently, battery life on the Z3 compact is even better!
LTE on MTN is fantastic! I got 32Mbps download and 9.8Mbps upload on speedtest.net at home with 39ms ping. I normally run the test twice as second time always seems to be quite a bit better, but the test used 75mb of data so I opted not to.
All in all, if the phone keeps beating, I think Sony have a winner here!!! I'm loving it!