1.
much the same; about the same; six of one, half a dozen of the other
Used when two or more things are so similar that there is no meaningful difference between them. Often implies that none of the options is particularly good.
どちらも似たり寄ったりだ。
They're both much the same.
Combines 似たり (being similar) and 寄ったり (being close), reinforcing the idea of near-identical similarity. The たり form of both verbs creates a rhythmic, set expression.
Usage
Often carries a slightly dismissive or negative nuance — implying that none of the options stands out or that they are all equally mediocre. Used as a predicate with だ or as a modifier with の.