The sub versus dub argument is one of the oldest fixtures in anime fandom, and it is largely a fossil. The strongest points on both sides were made about conditions that no longer hold.
It is worth retiring properly, because there is a genuinely interesting question underneath it that the shouting has buried.
What the argument was actually about
The subtitle case was built in an era when English dubs frequently involved cut content, renamed characters, replaced music, rewritten dialogue and edits for broadcast standards. Preferring subtitles was not really a preference about voice acting. It was a preference for the version that had not been altered.
That was a strong argument, and it was correct. It is also mostly answering a problem that modern licensing does not produce. Dubs today are generally made from the same cut, with the same music, and without the content edits that defined the era the argument comes from.
The dub case has weakened too
The counter-argument was that reading subtitles is work, splits your attention away from the animation, and keeps anime niche. Some of that still holds — you do look at the bottom of the frame instead of the frame.
But the claim that subtitles are a barrier has aged badly. Subtitled viewing is now completely ordinary across all kinds of television, plenty of people watch everything with subtitles on regardless of language, and reading them is no longer an unusual skill that marks you out as a hobbyist.
What genuinely still differs
A dub is not the same script in another language. It is a different edit. Lines have to match mouth movement, which changes phrasing and sometimes meaning. Jokes that depend on Japanese wordplay have to be replaced with something rather than translated. Honorifics and forms of address, which carry real information about relationships, either get dropped or get an English approximation that is never quite the same.
Performance direction differs too. The conventions of Japanese voice acting and English voice acting are genuinely different traditions, and a performance that reads as intense in one can read as overplayed in the other.
So the real question is not which is better. It is which set of trade-offs you would rather have, and it can reasonably differ by show.
The point nobody makes
Dubs are an accessibility feature, and this gets left out of the argument almost entirely. Subtitles exclude people who cannot read them comfortably — low vision, dyslexia, reading speed, or watching in a situation where you cannot look at the screen continuously.
Any version of "subs are objectively correct" has to account for that, and most versions of it do not. A dub is the only way some people can watch the show at all, which is a considerably better argument than anything about authenticity.
The answer
Watch the one you will actually pay attention to. If a dub means you look at the animation instead of the text, that is a real gain and it is allowed to matter more to you than fidelity. If subtitles mean you catch a performance you would otherwise miss, take them.
It varies by show, and changing your mind halfway through a series is a completely normal thing to do rather than a betrayal of a faction.