I stayed at this hotel for a week in October. It was one of the nicest hotels I have ever stayed in. I was on the concierge level in a room for one person (had a double or queen sized bed). It was very comfortable for one person, big enough for two if you are a couple.
The location is wonderful. We were able to shop for whatever we needed and walk through the underground shopping and department stores. I went for a walk through the train station and past the Nissan building to get to some walking paths along the canals. Very safe and beautiful.
The breakfast buffet was plentiful, including American, European, Japanese and other Asian styles of food and beverage.
To address some of the criticisms of other reviewers:
Yes, you will have to pay for wifi access. It cost me about $10 US for the week. Not really worth griping about, I'd say.
The temperature in the room was difficult to control. I figured out that part of the problem is the heated toilet seat. I had to turn off the heated seat in order to keep the room cool enough, or leave it on but turn the thermostat down significantly. Again, hardly a major issue - sometimes life hands you a heated toilet seat - not exactly a major discomfort!
We made use of the concierge lounge. It was pretty simple - some snacks and beverages. But it was just what we needed and the view was incredible! The only complaint I'd have is that they closed at 8:00 pm.
I was very comfortable at this hotel and would stay there again. I'd highly recommend it. One last note - Safety and security are my highest priority in travelling. On the way out the door on my last night at the hotel, I accidentally forgot to lock the safe in my room. I had left money, jewelry and my passport in the safe, and dashed out as the housekeeper was entering my room to clean it. When I returned I realized what I had done, and everything was still there. Needless to say, I was very relieved and happy that no one had violated my security.

The Yokohama Bay Sheraton is always our top choice to stay in Yokohama. The staff is super friendly and attentive to most any concern. Of course, the location next to Yokohama main train station is the most convenient connection to Narita Express, and most lines into Tokyo and surrounding cities.

Easy to get from Haneda or Narita airport through train or subway.
Hotel top class, COMPASS restaurant has american + asian food so in case is needed you can stay and eat. I personally choose to try all food on the sorounding areas.
Hotel is perfectly located above subway, train station and huge shopping center so no need to walk to much to take public transportation.
Attention from the hotels personnel is really awesome, nature of the japanese culture so no exception in this hotel.
Lowlights: price of dinner is 4000 yens (48 USD), quality is excelent but if you're not traveling for business reasons you can get a better price for similar meal outside. Breakfast price is less and worth it.
Rooms are clean and comfortable, to the american standard size would be considered as small but taking in mind that you're in Japan then is ok.
Prices of Sky Bar (top floor - 28) are really high, almost ridiculous, worth to visit from the view but just to take a picture because a beer for 16 usd!, you can get better beer and same enviroment in high class restaurants around the hotel.
Don't forget to ask the concierge for a map of the area that includes all public transportation routes.
Internet is available but depending on your room selection and package could be included or not, speed is good.
Includes A/C, lots of items for the bathroom, and of course the so famous toiletes with heated seats and automated rinsing function.

My son had his wedding here and we stayed at the hotel for several days. The wedding was beautiful. The rooms were nice (for Japan - a little bigger than other Japanese hotels). The staff was wonderful. It's very conveniently located to transportation (even Narita Express). The only reason I did not give it 5 stars because I thought it was way too expensive, but I'm afraid that is a complaint I have for all of Japan…I would say it was very nice to stay here.