I found this PSU (the 1300W one) on the cheap and decided to give it a go.
20 minutes. I was still installing the OS when I heard a loud POP and everything went dark. No burnt smell though.
And I can't have been overloading it since the GPUs weren't plugged in at the time. Only CPU, mobo and HDD.

I spoke about it with a friend who often works with China and he told me it is common practice for some companies to replace capacitors with cheap ones and sell them (the capacitors) back to the manufacturer.
That's right, your brand new Asus motherboard (or EVGA PSU in that case) might not have the capacitors the manufacturer put on it...
They manage to make a profit because human labor is cheaper than the price difference between crappy capacitors and high-end ones. Unbelievable.

So take this as a lesson guys. A piece of hardware from a reputable brand shouldn't be bought from a non-reputable vendor, especially if the price is abnormally low.
Now I have to try to RMA this pretty expensive brick, and not insult their mothers in the process...
At least my rig didn't seem to suffer in the process. I slapped an old Corsair 550W in there and it seems fine.