I went to the Seoul Plaza this weekend and was a bit disappointed. I expected a place that had a lot of hustle and bustle, but it was quite dead. Security Square Mall actually has a small section called Seoul Plaza that has a few korean shops, a small eatery upstairs, and the new Grand Mart.
The eatery upstairs was quite disappointing. They had a korean quick serve place open, and a korean owned pho joint called "Miss Pho." The Pho was OK, but for a large bowl, it was severely lacking in meat. The rolls were average too. Grand Mart was not so grand. The supermarket was not that big, and the prices were so so. Also, the place was almost deserted.
I also went over to Super H and it was quite busy there. They have a very nice food court that offers various korean, japanese, chinese, and sub shop type of options. The prices at Super H were decent, and they offer manager's specials. They have incredible produce, but I prefer Lotte's (EC) seafood section and meat section. Lotte's layout may be a bit better in that their cafeteria area is connected to the supermarket.