This place is legit. I've just got back from the past month in Tokyo and can tell you that if you want an authentic experience, this is likely as close as you will come to it in the states. You get to order your favorite type of ramen and add in any extras you like. The price is reasonable and affordable for what you're getting which is authenticity. If you're looking for something someone has taken their time on,and instilled with excellence you will love the resturant.
The customer service is likewise top notch and isn't overbearing. They made suggestions that complimented my meal even let me order extra noodles halfway through my bowl without having to get up to go back to the machine. The sake is fantastic and the beer list is very robust. Please give them a chance, you won't regret it.