I am comparing it to all my FujiFilm bodies and the other marque in my (as my beloved would put it) 'too many cameras' fleet.
Ken stated that the IQ was 'muddy' compared to the X-T4 and having tested it alongside my X-T4 and X-S10 (and for fairness sake my X-H1 and X-T3) I can find absolutely no difference in IQ between the newest bodies (X-T4/X-S10) which are marginally better than the older ones (X-T3/X-H1/X-Pro2) if you really start down the IQ pixel-peeping route. Its not a route I go down.
I have been more than happy with the IQ of the X-T4 and X-S10 but the subject aquisition and focus success rate of the X-H2S takes it to a different level above both of those super cameras and that is/was the rationale for buying it. As well as the phenominal speed and buffering and stacked sensor. That's on the FujiFilm 'compared to what' side.
If I then compare the X-H2S with my Sony A7 iv (my only full frame camera) I would say that the Sony is marginally better on focus speed, tracking and (pixel peeping) detail but, as I have more FujiFilm lenses and prefer the tactile feel of the Fuji's over the more clinical Sony, I am more than satisfied with the X-H2S. Each to their own!
His point that the IQ was no better or worse than previous much less expensive models was an irrelevance to me as I wasn't after a quantum leap in IQ (I am more than satisfied), I just wanted a much better focus and aquisition rate which I now have with the cracking X-H2S.
I like Ken and his thoughts on FujiFilm lenses just about mirror mine though I confess to not owning/using as many as him. But of those that I do own, they feature in his 'top-5'. I even prefer my 16-80mm over the bag of primes 16-55mm!
Whilst I do find his reviews very refreshing and interesting/different, I find Maarten Heilbronn, Andy Mumford and the Hybrid Shooter offer a more balanced viewpoint coupled with actual photo examples which I, as a simple retired soldier, can relate to and form an opinion/judgement on.
Unless I have missed them, I cannot recall ever seeing any actual examples taken by Ken to prove beyond all reasonable doubt, the contentious and (sometimes) contemptious and dismissive views he holds.
Again whilst I respect his views, I reserve the right to disagree with them and in the case of the FujiFilm X-H2S, I clearly do!
I hope that answers your point on the 'compared to what'.
I found this forum in a link from another Fuji forum so I'm glad to be here.
Regarding Ken, he's a strong, unique personality and part of his identity is to rattle the pots and pans. He's a quirky, intelligent person who has opinions, like we all do. His presentation can be extremely off putting, but he's worth listening to when deciding on a new Fuji.
I agree with others here who say it's best to rent a new camera if possible, and compare to one's own knowledge base and shooting preferences.