I would say 3.5
This is a small place, with tables quite close together. I came here near the end of the night so it was not too bad, but I can't imagine how tight it would be during a lunch or dinner rush. The menu was small, but fine by me. I had the Netsu, and my gf had the Yakisoba. We shared gyozas (was disappointed they had sold out of Takoyaki). The noodles and toppings were very good, however, the broth was so-so (I prefer the broth at Kinton). The surprise of the night was the gyoza though. They were quite large, juicy and tasty. Service was quick.
Overall, I liked the meal and food. I would come back if I'm in the area and felt like ramen; however, I wouldn't go out of my way to come back.