I love kimchi mandu, but not just any kimchi-du. Sometimes you get these awfully leathery ones with subpar kimchi and greasy meat. These are normally found on street markets and the infamous kimbap chun-guk. I recently went to Homilwon in Bundang with a Seoul Eats reader (and good friend) Ji-Yeon to Homilwon.
The mandu were huge, like little baby fists, and they were packed with a gingery, slightly sweet kimchi filling that was rippled with jap-chae noodles and tofu. The texture was exceptional- like a nicely marbled ribeye with a crumbly streudel topping. (Yeah, I know the favors don't match, but I'm talking about texture here.)
They were so good I had to take some home. (I was planning on sharing them with my roommate, but I get up earlier than her.)