The ANA does have an awesome location... it's close to EVERYTHING that's relevant in Tokyo. Most convenient if you have business in the Ark Mori, Sanno Park Tower, Izumi Garden or one of the other nearby office buildings, but it's also within walking distance of the government complex, the Roppongi nightlife district, and even Ginza if you have strong legs (alternatively, ride the subway 3 stops).

The other good hotels in the area (Okura, Akasaka Prince and New Otani) are way more expensive so ANA is quite a good deal, all things considered.