While the X lacked the flagship chipset and waterproofing required of a true Xperia Z5 successor, the Xperia X Performance ticks those checkboxes. And it has exclusivity on the brushed metal finish for its metal back (the back of the X is available in satin only).
The phone also carries over the 5" 1080p screen, which renders amazing colors thanks to the Triluminos tech, and the top-notch sound setup with the stereo speakers and 24-bit High Res audio.
The 23MP camera features predictive autofocus, which tracks objects and keeps them in focus automatically. It's an improvement over standard phase-detection AF thanks to the additional smarts (the 'predictive' part). And you get a 13MP selfie camera for better self-portraits.
The camera has a downside - it can't shoot 4K, but does offer 1080p @ 60fps. To be fair, the Huawei P9 has a similar limitation.
Harder to defend is the regional availability of the fingerprint sensor (not available in the US) and the water resistance. Yep, some regions don't get you an IP rating, at least as far as warranty is concerned. Having only 3GB of RAM isn't ideal, neither is the 2,700mAh battery.
Availability is more limited than the Xperia X - both regionally and as timeframe. The Sony Xperia X Performance is available only in Taiwan right now, while buyers have had months to jump on an S7, G5, HTC 10, P9, etc. And they paid less too.
So, are you holding out to buy an X Performance? Or are you giving Sony the cold shoulder?
Where can I buy this phone in China ？
IMO maybe many people have been brain washed by the competitors's keyboard warriors.