My stay in Sei's apartment was excellent.

Apartment:
The apartment came well furnished, with all appliances functional as well as little extras such as spare phone chargers. Hangers, clothes pegs, toothbrushes, plates, slippers, cutlery and the like are all readily available. The beds were extremely comfortable, comparable and (to me,) even better than what you get in a hotel. As indicated, there is also a portable wifi free for usage.

I value the microwave a lot, for it allows you to grab late night snacks from convenience stores and heat them up yourself.

Service from Host:
Sei is an excellent host. She recommended a change in rooms when she noticed that we had 4 travelers, mentioning that the previously chosen room would be less preferable due to the number of beds. Changing over was the correct choice, I believe. We requested her to help us get a parcel from amazon and she did, dealing with the problem when the item turned out missing and also providing phone support in dealing with the deliveryman.

We had our baggage delayed during our trip as well. Sei deftly coordinated the collection of baggage, leaving it in our apartment while we were away, allowing us to carry on with our itinerary.

Conclusion:
I really enjoyed my time in Tokyo at Sei's apartment. From amenities to service, everything here rivals what you get from a hotel stay. In fact, the rooms are much bigger and better furnished. To I never thought it possible to have such excellent service from an airbnb host. For a peace of mind, excellent service and apartment, go with Sei. :)

*One caveat would be the potentially throttling portable wifi. The wifi seems to work with a data limit that refreshes each month. Once the data usage limit is reached, the internet starts throttling, only giving low speeds. Apps like whatsapp are still usable, but it ends there. Having arrived at the end of the month and leaving at the start of the next, the wifi was only usable without throttling on the 1st of the new month. The throttling of the wifi is difficult to control given that it depends on the usage of the previous visitors. I suggest on getting your own mobile sim / wifi. Doing so makes splitting up easier as well, if you're traveling in a group.