Reading it in Japanese is cuter.
For example, (almost) all the stuff Yotsuba says is in hiragana. Even when using the same words as where kanji is used for adults.
Additionally, all her text is in larger font and bolded, while the adults' text is in unbolded small font, to indicate that she's always shouting.
Those kind of things get lost in translation, which is a very sad thing, because it's very cute.