At the end of the day, the CSP-X1200CB left me with mixed feelings. On the one hand it showed high efficiency, quite good voltage regulation at +12V and very low ripple/noise on all rails. Also +12V and 5V performed well in the very tough Advanced Transient Response (ATR) tests. On the other hand, voltage regulation on the minor rails was loose with 3.3V registering a huge 6% deviation - beyond the ATX spec limit of 5%. On top of that, the same rail failed in the second ATR test, indicating that the 3.3V voltage regulation module definitely needs tuning. The last drawback I spotted, was that the unit couldn't deliver full load at 50°C ambient. As soon as I dropped the temperature to 45°C it operated smoothly and finished full load tests without any problems.
I find it odd for 1200 W power supply to not allow the use of six PCIe and two EPS connectors at the same time. If you connect two modular cables with two PCIe connectors each (the other two are hardwired) then you can't connect the cable that holds the second EPS connector (the first is hardwired). Also power distribution is not optimal.

Although this PSU exhibited very good performance in some areas, it also performed mediocre in others. I would prefer to see a more balanced performance overall. Especially the 3.3V rail troubled me the most, a 1200 W PSU should not have any such problems. If the Club 3D CSP-X1200CS came at a slightly lower price, could handle full power at 50°C ambient and 3.3V performed better then it would easily earn our recommended award.