I bought Sony xperia z1 in january 2014 after doing several researches online and offline(visits to sony store). There were numerous reasons for buying it at that time. The Sony Xperia Z1 boasts modern specs worthy of a flagship smartphone, including a 5-inch full HD 1080p display(441ppi) sporting Sony’s TRILUMINOS screen technology and X-Reality for mobile. Sony has packed some serious firepower under the hood, a 2.2GHz Qualcomm Snapdragon 800 processor with 2GB RAM, 16 GB internal memory and Adreno 330 graphics. But from my point of view One of the highlights of the Sony Xperia Z1 is its camera, with Sony’s own G Lens with 27mm wide angle and f/2.0 aperture. It clicks stunning pictures, and records full hd videos in every lighting condition. But it is no more upgradable to latest android version after getting android lollipop 5.1.1.
I was happy till the official launch of 4G/LTE. Only then I got to know that this power packed handset is incapable of running on 4G.
So if you are looking to buy xperia Z1, buy only C6903.