Please, don't tell me that you always use "格好良い" or "良い". Have you heard of "イケてる"?
"格好良い" means "to be cool" which is mainly used to describe a good looking person or a stylish thing. "良い" means "to be good" which is used to describe a person with good character or the good quality of something.
"イケてる" is slang for the above words and the negative form is "イケてない".
It is said that "イケメン" is derived from "イケてる男(men)" or "イケてる面(顔)". "イケメン" means a good looking guy.
Meg and Amy are talking about their favorite singer's song.
- Meg: That new song is awesome, isn't it?
例の新曲イケてるよね？ - Amy: Yeah! The melody is amazing so are the lyrics!
うん！曲がいいだけじゃなく、歌詞もイケてるんだよ！
Ken and Leo are talking about the new colleague who is from the US.
- Ken: Do you know Sara?
サラって、知っている？ - Leo: Are you referring to the woman who was assigned to our project?
俺達のプロジェクトに配属された子の事？ - Ken: Yeah, she is so hot!
そう、彼女マジ(で)イケてるよね！ - Leo: I knew it. I was going to ask her out, but I couldn't imagine talking to her in English. I just felt immensely uncool. (Sigh) I think it would be so cool to speak English fluently.
そうだね。デートに誘おうとしたんだけど、英語で話しかけるなんて想像できなかったわ。イケてねー(イケてない)。英語がペラペラに話せたら、イケてるんだけどなぁ。
Ken and Leo are reviewing their documents for a meeting.
- Ken: What do you think about our documents? Do you think we'll be able to satisfy the clients?
資料、どう？お客さんに満足してもらえるかな？ - Leo: I think we were able to put our ideas together. The contents are awesome, but the appearance needs some improvement.
俺達の案はまとめられたと思う。内容はイケてるんだけど、見た目がイマイチ(orイケてない)。 - Ken: All right. I'll fix it up.
了解。修正するよ。