We just stayed on an award stay for 2 nights at Tokyo Bay. As gold, we were upgraded to exec floor and given free breakfast in the exec lounge (which closes at 5:00 pm every day). We were the only people eating there each morning, while the restaurants had long lines, so that was really nice. Because the lounge closes so early, you can't have evening snacks and cocktails like in Tokyo, Osaka and Nagoya. The room was not special, but not bad.
We did get 4 coupons for the minibar (4 items free), but for the first time ever, our daughter had to pay for breakfast (she's 7)...and they gave her a discount coupon for the lobby lounge breakfast buffet, but gave my husband and I free breakfast coupons only usable in the exec lounge...I guess they expected us to eat seperately! In the end, I was able to use the coupon for the lounge breakfast for her, but I had to fight a bit for it, which was a first for us in Japanese Hiltons....we've never even had to ask for anything really before. We got free use of the pool and health club...pool was OK, not as nice as Osaka or Nagoya (never used Shinjuku's), and health club was well equipped with mostly very old Nautilus equipment - though there were 2 new LifeFitness elliptical machines in there too.
The new restaurant "The Square" was EXCELLENT. We chose to have dinner in the Asian section of it (there is also a Mediterranean section), and it was a kind of "made to order buffet" with foods from all over Asia, arranged by country in stations manned by chefs. It was very, very good food and excellent service. I'd go back just to eat dinner there again I think.
Location...it's good. We got to Haneda airport in 20 minutes by shuttle bus and were able to get on an earlier flight home, which was lucky. It is well connected to the Disney Line with a shuttle bus or a 2 minute walk...and the Disney Line connects to the JR line. If you had reason to be in the Tokyo Bay area/Odaiba then I'd certainly recommend Tokyo Bay.