While that video was a good test to demonstrate the ability of the microphones to distinguish between the voice and the ambient noise, the ambient noise obscures the self-noise of the microphones. It would have been very helpful to hear all those microphones at the same gain into the same recorder, but in a noise-free environment. Perhaps buried inside a great pile of pillows and blankets inside an interior closet at midnight.
One of the risks of buying inexpensive gear like those microphones is the possibility that the performance may not be consistent from one year to the next. As sources of parts (especially the commodity condenser mic capsule) may come and go. The only reliable method of determining actual performance might be to actually try it for yourself if you can get your hands on them to test. Of course, higher-price, “mainstream” microphones would have a better expectation of consistency.
I would have somewhat higher expectations from JK than from some of the “no-name brand” products.
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Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.