I've stayed at Kanda, but not that Higashi Nihonbashi. Google reviews seem generally positive. I have found Comfort Hotels in Japan to be very consistent. The only real difference is the size of the room. Singles are really tiny, as are most doubles. When using points, booking a twin is always better than a double (same amount of points). I once booked a twin with sofa (accommodates three) for two adults, but found out it was the same size as a regular twin and the sofa was just in the way, so that strategy isn't anything special.