They are well-made, though there are no markings on them whatsoever. I have been using them to light the (totally) dark corners of our corridor; they are a lot brighter than I would expect, plus the warm-white variant I bought generates a very pleasant shade of white. One such downlight in a fitting mounted about 2m above ground will light an area of about 1m square. The light is not strong enough to read comfortably with, but it is fine for my purpose (i.e. corridor lighting).
I haven't a light meter so I cannot verify the lamp produces 100lm as advertised but as stated earlier, it certainly is bright!
I took the following measurements using a variac and a true-RMS multimeter (all values AC, measured at 50Hz):
Voltage Current Power
100V 11.4mA 1.14W
117V 9.6mA 1.12W
220V 5.6mA 1.23W
240V 5.4mA 1.30W
The measurements show that the lamp actually uses a "proper" switchmode power supply. The light output does not change much with varying voltage, though the change is perceptible.
The two pictures attached are the waveforms of the current drawn by the lamp. The more "rounded" waveform is with the lamp run at 240VAC, while the "spikier" waveform is with the lamp run at 117VAC, both 50Hz.
Finally, the lamp has a very substantial and effective heatsink, and hardly gets warm at all.