This hotel is well situated near Ueno JR and metro stations and also close to the Skyliner train from Narita. It's a comfortable and well maintained hotel with most features one expects nowadays, including internet availability in the room. There are also washing/drying facilities at a reasonable price, and drink vending and ice machines on each floor. Reception staff were pleasant and helpful when asked and met all our needs. The rooms we were offered were on the small side, with limited shelf space for clothes and toiletries, but overall just adequate. Our only other experience of a modern Tokyo hotel was the Hotel Century Southern Tower in lively Shinjuku which was quite spacious by comparison to this hotel, cheaper, and only one subway station from the Skyliner line from Narita.

What's good:
It's right next to Ueno JR station. In less than 10 minutes, with a straightforward walk through some easily navigated subways you can be on the new Keisei Skyliner express train that take as little as 40 minutes to Narita.
The room was small but well equipped and comfortable and you can hardly hear outside. Only one pillow per bed plus a little cushion.
What's not:
That convenience is very expensive. The breakfast is atrocious. It starts at 7, and a line forms for that early, then it's a narrow line past a poor collection of budget-hotel style offerings and a bit of pasta. The tables are so close that you can hardly get in.
Service. I asked if they could print my boarding pass pdf. They smilingly directed me to a print shop over the road!!! My wife asked for help with the bags. They wanted to charge her.

We stayed at the Mitsui Garden over Mother's Day weekend. We had three rooms. The rooms are small compared to U.S. standards but standard compared to other Japanese hotels. Rooms were clean and service was excellent. Some staff spoke English. Hotel very convienent (Exit 1 on the Ginza line). There is also a Tokyo tourism office at the Ueno office. Yes - it will be nice for WiFi throughout the hotel. We got one of the WiFi "packages" but was not able to access from our rooms. Restaurants near the hotel were small that served mostly noodles. Enjoyed the easy access to/from the Tokyo Metro line.