I have the xperia x performance and is way better than the z5 premium. It is the best xperia smartphone yet and this is coming from a guy who owned the z2, z3, z5 compact, and z5 premium. Although it cost a lot more than other flagships this year it is completely worth the money. No other flagships can compare to this amazing phone. I get 6 hours screen on time playing epsxe (ps1 emulator) connected with my dual shock 4 wireless with Bluetooth. I do a lot of gaming and watching YouTube videos and can get 6 hours of screen on time. If you use the x performance casually you can expect up to 7 or 8 hours during my testing. The camera is impressive and is better than the s7 edge when using it during the day. However the s7 edge is slightly better than x performance when it comes to low light scenes. The display of the xperia x performance reminds me of an oled display since it's so vibrant. But don't worry it's not overly saturated like the s7. Outdoor visibility is amazing and the speakers are loud and clear. Overall this was totally worth my money and will use this device as my daily driver. By the way don't listen to the reviewers like phone arena, CNET, GSM arena they are all biased and only you can chooses if the x performance is for you.
