I've eaten here twice, once for Summerlicious and once for the regular menu. I would not recommend eating here if vegetarian, as I tried the ginger scallion noodle and found it underwhelming. There were a lot of toppings and they were mostly pickled in vinegar, which made for repetitive flavours. I tried the jjajang noodle the next time I returned and found it a bit too sweet. The presentation of the food is generally consistent and quite nice, though it always looks better than it tastes.
The atmosphere is always busy and it suits the setting -- with long benches and communal tables, and chopsticks and napkins out of a dispenser. I think if looking for a quieter meal, Daisho upstairs might be a better environment. Both times I visited, my party was done eating within an hour, and it almost felt like they were trying to vacate our table to accommodate others.
Overall, I would recommend a few other ramen places over Momofuku -- it's not particularly worth the extra few dollars.