Just got around to test the things.
The module is not capable of delivering what's promised by the datasheet.
Part of the problem is most likely that there's a inductor soldered on the board marked "220", which I'm guessing stands for 22 * 10^0 µH instead of 220µH.
Would explain almost 0,5Vpp (measured with Multimeter - after seeing this, I didn't bother with the scope) slow frequency ripple and the fact that it's barely capable of delivering 40 mA.
So at least there's a different inductor required, or, in case the chip itself is fake, a new chip as well.
In other words: Not worth even 1$ in the form I received these modules.