Incredibly well prepared with a lovely and precise written guide to the apartment, the surroundings, shopping etc. Couldn´t be better.
The apartment itself: for Tokio relatively spacious bedroom and bathroom, a small attached terrace in an area that´s famous for French and Italian restaurants. Iiidabashi with 4 helpful Metro lines 3 minutes walk away. It´s not cheap, and price wise on the level of a 4 or 5-star hotel. If you prefer privacy, know the city a bit and don´t need a reception, this is the better option.
The last 2 days WiFi crashed, which in Tokyo is a bit of a drama, since there are hardly any open WiFi spots for foreigners. You´re literally disconnected, and for me, being on a business trip, this was a bit of a desaster. Not the hosts fault, probably, but still pretty unpleasant.
Masa himself is incredibly helpful and proactive.