The apartment was everything we expected it to be—it was nice, clean and well-appointed, and looked exactly as it does in the photos. We we were also sufficiently warned about its close proximity to the trains, so the noise was anticipated. It is also just a few minutes away from the Yurakucho, Hibiya and Ginza stations, so it's very conveniently located.
Mas-san was a great host, picking us up at Yurakucho Station when we arrived and even offered to arrange a sushi dinner and Tsukiji tour for us. He was very accommodating and made sure to check on us every once in a while to see how we were doing.
What I was not prepared for was the absence of an elevator in the building, which is quite old. We traveled with heavy luggage and so it was quite an ordeal to go up and down 4 flights of stairs, so I wouldn't recommend it to those with plenty of belongings. Guests who like to shop might have difficulty coming home and making the trek upstairs on their own with tons of shopping bags. Otherwise, if you don't mind the effort, this is a convenient base to stay in Ginza, and Mas-san is great host who will ensure you have a pleasant stay.