I like Korean supermarket. The products are more fresh and healthy than the ones from mainland China. The products may be a bit expensive than the ones from Chinese supermarket but still in a reasonable range.
The special thing of the supermarket is there's a cafeteria area inside. If you are rushed for you lunch, you can picked up some ready-made dishes for your lunchbox. Some dishes are as good as regular Korean restaurants. Don't forget the steamed rice, it always goes with Korean dishes if you want to try the food in a more Korean manner. This more buffet-like way, I think, it's really a fast way to get your stomach filled nicely.
You can also order the food from menu. And it won't make you wait for too long.
Overall, it's a good place for shopping and eating. I would recommend the place for my friends and for you.