We only had one day in Tokyo, as part of an extended layover, so needed a place that would be both convenient and relaxing. The Conrad delivered on both accounts.
The location of the Conrad is very helpful for the early morning Tsukiji fish markets, which are perhaps a 15 minute walk away. The metro is nearby (you barely need to go outside) and if you take the Skyliner train in from Narita as we did then you can reach the hotel on the metro on a single metro line which is convenient.
We found the staff at the hotel to be very helpful. The concierge set us up for a wonderful dinner at a great restaurant for our one night in Tokyo, and the staff took care of briefing the cab driver for us too. One note: the lobby bar has a dress code - they made me go upstairs and change out of my sandals before they would serve us, which was annoying but a minor blip and not altogether surprising given the high-end nature of the hotel.
Overall, a good experience and one I'd be happy to repeat.