I visited Obaek Guksu Siheung Neunggok recently. After some hesitation I ordered the mandu kalguksu, and overall the dish was quite satisfying.
The kalguksu noodles were the familiar, common style you often encounter, but the dumplings that came with it were impressive. There were about three large meat dumplings packed in, so it was filling enough. Above all, the broth was excellent — it had a deep, rich flavor that suggested the shop takes care to simmer the stock, which I really liked.
It wasn't a flashy flavor, but the solid, well-executed basics made for a pleasant meal. If you're nearby and looking for a light yet satisfying meal, I recommend stopping by.