"Mr. J is a person like no other"
 

How do you say, "Mr. J is a person like no other" in Japanese?

I don't know if the nuance is there, but you could just say something as simple as Jさんはユニークな人.

However, I have to warn you that without more context it is very difficult to get the meaning across. In what way do you mean he's a person like no other? Do you mean it in a good way or a bad way? Is the person a jokester or serious? What type of situation do you plan on saying or writing this in? It all depends.

I mean it in a GOOD way, and I kinda don't want to use "unique"...

dictionary hint: “like no other”の検索結果（50 件）：英辞郎 on the Web：スペースアルク