We really enjoyed staying at MONday Apart Premium Ueno. The location is perfect for our family. Its close to the Ueno park and MRT station and has some great coffee shop not to far from the apartment.
The Check-in time is at 3 PM, but you can leave your luggage at the lobby if you came in earlier. The room is only cleaned every 3 days, hence if you only stay for a short time, you won't have the room cleaned. But for longer stays, its nice to have the room cleaned every few days. The laundry machine is also very helpful for us since we stay for a long time in Japan. The in-room laundry machine has a Washer and Dryer feature, which is perfect for us.
The extra bunk bed is also nice for out little kid to climb up and sleep during nap times. Overall, its a great accommodation for us in Tokyo!