There are reviews which really really baffle me as well - I did a review for a TV I bought off of Amazon.co.uk in the Black Friday sales - it was a Seiki 4K 39" TV at a reasonable price.
It arrived, I set it up and the sound was terrible, so I used an external sound bar - but there was horrific video lag regardless of the input used, it was between a third and half a second behind the audio. Also there was no way to set the TV audio to just optical out, you had to either mute the sound entirely (which left a mute symbol on screen) or turn the sound down to 0 (which wasnt actually off, you could still hear it). Moving the audio out to the Sky box reduced the audio lag but didn't eliminate it, but at least you could set a delay on the audio out on the Sky box which brought it into line - but didnt solve issues if you have a second device such as a console etc.
There was also horrific tearing and artifacts on the screen - someone moved and they left a wake behind them.
Testing it all with the no-name TV I was replacing had the soundbar working fine, the Sky box working fine etc - no setup needed, no lag involved, no tearing of the picture etc.
So back it went, and I replaced it with a slightly more expensive TV which has had no issues whatsoever since.
But what I don't get is all the "works great!" "Brilliant!" reviews the TV is getting...