Too much advertisement? Well, didn't we all learned to ignore it by now, and use own gray wetware to decide on deals?
That is not how this works. If I will be looking for precision test gear I would value your opinion higher than some random comment from 9gag. The same with TheSignalPath, being an RF noob, I would take his advice seriously any time.
Look at the YT comments under this video:
"...I love their bargain prices..." (strange to hear about a company that sells an old used 3458A for 66% of the brand new price),
"Will keep AllTest in mind for next purchases."
"Good on AllTest to 'sponsor' this!"
"Glad to know about AllTest"
"I'll definitely consider Alltest for my next instrument purchase."
So either some troll army or the endorsement works.
I realise that these video blogger - company relationships are difficult and it is a fine line.
My gut feeling tells me that big brands are probably safer, as while there are no saints (Adafruit - Fluke case ,FTDIgate, Siglent trademark troubles), their primary focus is to develop new products that can be reviewed on their own merit and in the end it somehow benefits the community, even if only 20 years later when the second hand prices become affordable for a hobbyist.
At the same time most equipment traders work against the community, using their power to take truckloads of surplus/auction equipment off the market and as people have mentioned sell some way above the market prices and the rest as cannibalised units for parts.