I'm usually in the "subs are objectively superior camp". However, there are exceptions where I would consider the dub to be objectively superior to the sub:
Steins;Gate: The characters English voice actors really spring them to life and give them personality. In contrast to the Japanese voting actors who make them seem generic or even off-putting. Kurisu in the English version sounds like an intelligent and proud young woman, who does have a shy side she desperately tries to hide. In the Japanese version she is lacks her intelligent and proud persona, and seems to be just a nervous shy girl who always seems to get borderlined bullied by the main character. Mayuri is even more ridiculous. While she admittedly seems a bit "off" in the dub, with the sub I believe that she is literally mentally challenged with how "out of it" she seems.
Dragon Ball Z: The dub just simply nails everyone. While the sub is okay, it doesn't "match" the characters anywhere near as the dub does. Also, I don't give a shit how iconic the voice is, Goku's dub is terrible. Yes, he's essentially a kid in an adult's body, but an adult has an adult voicebox. Hence he should speak like a kid, but not sound like one, just as the dub portrays.
Cowboy Bebop: Similar to Dragon Ball Z. The sub is serviceable, but the dub is incredible. The casting team continually caught lightning in a bottle with all of the main cast.
