In that very video he states that it is his first subwoofer. His first, I insist...
I already addressed that.
Yes he expresses delight in how the subwoofer filled out the KEF LS50s he often uses. Not surprising in a subwoofer review. But it's not like he's unfamiliar with low frequency extension. As I mentioned he does a lot of headphone listening so he would be quite familiar with the low frequency content in his favourite music. And he'd previously reviewed for instance active speakers by Buchardt, Dutch & Dutch, the Kii Audio Three...all of which have quite deep bass extension.
Since there is low frequency information in many if not most genres of music, you may as well say that someone can't be a "real" informed enthusiast unless they had a subwoofer, which seems like more of a strange purity test. Classical music for instance often contains bass frequencies most aren't getting in their home system. My father-in-law is a classical music fanatic, huge library, extremely knowledgeable. But his speakers aren't full range. No sub. It would be silly for me to attempt to deny his passion and knowledge of the genre "because he isn't using a subwoofer."
This seems more a desire to take a dig at a subjective reviewer than a cogent criticism.
In that video there is nothing I couldn´t find in KEF´s website. Joe´n Tell at least gave measures.
Anyone can read manufacturer specs and claims about their gear. Darko gave what people came to hear: a general guide to the use of subwoofers for those who may not be so familiar, the KEF in particular, and most importantly, people come to see his presentation of
a user experience - what it was like using the gear, setting it up, dialing it in, the subjective effects of the subwoofer paired with different LS50 versions, the effect of using the high signal connection vs low/high pass crossover filtering, what in the end he preferred, etc.
One can always say "he didn't offer anything informative" if...well...you ignore, or don't care about, the type of information he offered. And, the comment section shows plenty of people - all of whom could read the KEF literature themselves - got a lot out of his review.