This is the older of the 2 hotels, it is in a nice setting and only a few minutes stroll you can get to Shinagawa train station, by far the best way to get around. Anyway the hotel is OK, rooms are clean and fairly spacious, my wife likes the heated toilet seat! Food in the hotel along with drinks are expensive, head for the train station and there are several better eating options as well as small supermarket at the station entrance. If thinking of shopping in Japan then do your homework first and check your local prices, we found that the UK was cheaper for many items, but some were good deals.

We stayed at the Grand Prince Hotel Takanawa together in mid-May for 4 nights (my husband stayed an additional 4 nights). Our room was very modern and comfortable. The amenities included hot water dispenser (kept full by housekeeping), tea, and minibar. There was no coffee provided, so we bought a jar of instant at the convenience store. The mini-fridge allowed us to also buy yogurt for breakfasts in our room (have to find some ways of saving money in expensive Tokyo!). The staff was very helpful and polite, and the hotel was convenient to reach via the Friendly Airport Limousine bus. Internet was available in the room for 100 yen per day. There were no English-language channels on TV, but it was fun to watch some Japanese programming. The hotel is close to Shinagawa station, but beware it is located on a hill, so the trek from the station to the hotel after a long day of sightseeing can be tiring.

My favorite part of the hotel is the lovely Japanese garden behind it (shared by several hotels in the area). We had a garden-view room, so it was not only nice to walk through it, but also nice to enjoy the view from above. There is a tea-ceremony building within it, as well as a shrine, and a large pond with lots of koi.

My wife & I recently stayed for 4 nights on arriving at Tokyo & 1 night on departing. On arrival, our pre-booked, pre-paid deluxe garden room had been allocated & no more were available. Accordingly, we were upgraded to a Junior Suite on the 14th floor with views of the Tokyo Tower and city area. Unfortunately, the room had an overpowering musty smell, the furnishings were old and well-used & the carpet had both holes & stains. As it was 11.30pm & we'd been travelling for 18 hours, we decided to sort out our accommodation the next morning
We requested & obtained a deluxe garden room on the 12th floor with views of the garden & the other 2 Prince hotels on site. While smaller, this room was much more modern and better furnished than our 'suite'. It was relatively spacious, containing 2 small armchairs as well as a writing desk & chair. There is a door to close off the bedroom from the entrance corridoor where the wardrobe, minibar, tea & coffee making facilities & refrigerator are located.
The bathroom contained a bath & shower combined, bidet & was well-stocked with toiletries.
The hotel is only a 10 minute walk (downhill) to Shinagawa Station & there are numerous restaurants, cafes, mini marts etc there & in the immediate vicinity of the New Takanawa Hotel on the other side of the common garden area. While the hotel operates a shuttle between the 2 Grand Prince Takanawa hotels & the Prince Hotel, it only runs of a morning & late afternoon.
10 minutes walk in the other direction is the Takanawadai station, on the Asakusa Subway line, which goes directly to Asakusa Station for those wanting to visit the Asakusa Kannon temple complex & Nakamise Arcade to do some shopping.
This subway line is also convenient for visiting the Edo Tokyo Museum - change to the JR Line at Asakusabashi station & travel 1 stop to Ryogoku station.
All staff we dealt with were friendly & helpful & all had rudimentary English language skills with some being quite fluent.
I can't comment on the restaurants as we didn't eat at the hotel.
As others have mentioned, air conditioning seems to be a problem at this hotel. The thermostat in our first deluxe garden room could be set between 18 & 25C, but we were never able to get below 21C despite selecting 18C & running the fan on high. On the second day of our stay, we returned to find the air conditioner not working at all. I rang reception & spoke to 2 different people before someone from maintenance was sent up. He asked me to ring reception again, which I did, & after an animated conversation he passed the telephone back to me & I was advised that the air conditioning was shut-off every afternoon until 5.00pm because of the 'changing of the seasons'. It was 21C (approx 70F) & humid outside and 25C (approx 77F) & very warm in the room, so the maintenance officer obtained a fan for us.
Bizarrely, the air conditioning came back on at 4.10pm & was on when we returned at 3.30pm the following day.
On our second stay at the hotel (1 night in a different deluxe garden room), we were greeted at check-in with a sheet of paper advising us that all power - including that for air conditioning - would be turned off between 1.00 & 6.00am the next morning for maintenance. This room, however, was much cooler than the first despite being on the same floor & the same side of the building.
Another surreal experience on our second stay was looking out our window and seeing all the fishponds in the garden empty & the fish apparently happily ensconced in the outdoor swimming pool.
In our view, the hotel is conveniently located for travel within & beyond Tokyo but has little else to lift it above average in terms of an overall assessment.

the hotel has a good location - it is a 5 min walk from shinigawa station and a very helpful guest relations desk. the room was clean, but the ac took a while to work. there is a very nice garden and pool in the back. you can walk through the garden to get to the New Takanawa Prince Hotel. there is free internet access and shuttle service to and from Narita airport (you need to buy a ticket in the airport). the hotel also provides yukatas (japanese pjs for your stay in the hotel). all in all a decent hotel.