If anything, that enhances his credibility (even when I disagree) in my books because he can update his opinions based on the changing facts.
Both Android and iOS are continuously updated and opinions that used to be valid aren't necessarily valid later.
Likewise with different phones. If I've only ever used Samsung phones, then I might be tempted to think that modern Touchwiz is "light" for example (as opposed to just "lighter than it used to be"). The fact he has used so many different phones gives him perspective.
Zorachus
I would expect the screen to be brighter and better than the V30's. Almost nobody disputes Samsung has the better OLED screens for phones right now. I also don't see any particular reason why the X should have hugely different battery life from the iPhone 8+ on average.
So when I say I've used multiple phones from both sides and call a spade a spade, some people take that in a negative way. Yet when somebody else literally does the same thing as me, they get praise.
/shrug