As others have mentioned, it really depends on what you want to do in Tokyo. I stayed at the Conrad about a year ago and found the neighborhood quite boring. It's quite convenient to the several key train and subway lines, but the neighborhood itself felt a bit sterile and corporate. We arrived in the evening on a weekend (about 8:00) and the surrounding blocks were completely empty. I think there are a few attractions nearby, but I personally would stay somewhere else.

It is, however, a beautiful hotel.