Loose voltage regulation at +12V and 3.3V
High ripple at 3.3V during CL1 test
Performance of +12V at Turn On Transient tests
Quality problems on the modular PCB
Chinese caps used all over
This is the first Xilence unit that I ever tested and overall it left me with positive feelings. I encountered a very annoying usability issue though. The ATX connector on the PSU side requires a lot of force for the cable to be inserted, and to disconnect it I had to use a screwdriver to lift the little latch on the ATX power connector and release it from the socket. A similar problem was present with the modular PCIe connectors which required a lot of force to be connected properly. In a modern, expensive and high-end PSU I wouldn't have expected such usability/quality control problems, but on other hand I might have received a bad sample and the normal retail models do not have this issue.
During our performance testing the PSU performed fairly well, registering high efficiency throughout the whole load range and even under excess operating temperatures. Also contrary to my expectations the two small fans were fairly quiet and barely audible at lower loads/ambient. Moreover ripple suppression is excellent (except the unlikely scenario of CL1 test) and performance of +12V at Advanced Transient Response tests was outstanding. If Xilence could make +12V voltage regulation a bit tighter and lower the price tag by at least 20 bucks then I think that this unit would handle the tough competition much more easily.
To sum up, if you can afford it and want to try a PSU with unique design, good performance and silent operation (at least at normal loads and not at inferno-like operating temperatures) then the XQ Series 850W could be worth a try. However at this price tag you have lots of choices among other high-end PSUs from renowned companies with better build quality and loaded with Japanese capacitors that promise longer life-time.