Had lunch twice in 4 days in Mappen and thoroughly enjoyed it in both these occasions. I went there by recommendation by a Japanese friend of mine.
Just in case you don't know what Mappen offers, this is not a Sushi bar/cafe. They specialise in noodles in a bowl, and the service is what they call "self-service". Thus, the price-point is extremely low, at about $4~6 per meal unless you want lots of add-ons.
First, you order at the counter as you queue up, they make your meal on the spot and give it to you. Next, you have a choice of adding any deep-fried "tempura" side-dish(es) to your meal. This is optional. At the end of the counter, you pay for your meal. You then have to find a place to sit (you aren't allowed to secure a table before you get your food). After you've finished your meal, you RETURN your tray/bowl to a "tray-return" corner. This is a "self-service" cafe.
I particularly liked this system because, when you know you are going to pay around $4~6 (or, say, $10 with add-ons), you just want something quick and reasonably nice. And that's exactly what Mappen has to offer. I am happy to look for my seat, and I am happy to return my tray and bowl to the tray-return corner by myself.
And lastly, the taste. Surprisingly NICE. Perhaps it is because you know you've only paid a small amount of money for your meal?? But really, their noodles are strong, not soggy, and very filling. Mappen is quite close to my office in the city so I know I will return many times.
If you own or manage Menya Mappen, register now for free tools to enhance your listing, attract new reviews, and respond to reviewers.