I've stayed at the Akihabara location and can highly recommend it. About 5 minutes walk from JR and about a minute walk from the Ginza line. Nice bath on the top floor that has 1 large indoor, 1 large open-air and 1 small open-air tub (at least on the men's side.) If I remember right it also has a sauna. It also has a decent breakfast at a very low price (no viking too!) Bookable on the Rakuten English site. The single is of course business class small but does have a small tatami section which is a nice change from the usual business class hotel room.