ワードアップ英会話 WORD UP ENGLISH CLASS | 日記 | Idioms: "double-edged sword" / "cuts both ways"

When we say something is "a double-edged sword," or that "it cuts both ways," we mean that it has both some good points and some bad points.

So, for example:

Reiko: So, do you like living in Tokyo?
Finn: Yeah, but it's kind of a double-edged sword. I'm having a lot of fun, and the convenience is nice, but it's also really expensive!

Here, Finn could also answer, "Yeah, but it kind of cuts both ways." In both cases, he means there's a good side and a bad side to the situation.