See my post
#25 above.
He has a dev account. He posts LOTS of videos covering early betas, public betas, public releases, speed test differences, and so on. He even crawls through almost every interface of every stock app/settings/etc, checks out swipes/gestures/button behavior and finds even the most trivial differences between them. As an example, he posted this video yesterday:
He's exceptionally thorough.
People are really taking the "don't install iOS 12" video the wrong way. How many times do we hear on these forums regular folks shouldn't install betas, especially early dev betas. His video essentially supports that sentiment showing some of the very real risks.
He continues to be very positive about iOS 12, he was simply warning people that installing an early dev beta does come with risk.
And as I said in my earlier post, he's been posting vids for over 9 years and has over 5.6 million subscribers and specializes in these OS releases ... he's not some clueless dork complaining that a dev build dorked up his phone and is confused why.