I have stayed at the Palace in an entry-level room last November and really enjoyed my stay there.
Decent hardware and room size, very friendly and excellent service with true Japanese hospitality. Club level guests receive a great welcome check-in by getting whisked straight to the lounge (which I received accidentally due to a misunderstanding of my name by the bell man when I entered the hotel). I enjoyed sitting outside during breakfast in balmy weather, the buffet was of excellent quality.
I remember getting served my fav Italian sparkling wine, a "Ca Del Bosco Cuvee Prestige Brut Franciacorta" at 'Grand Kitchen' which came by happy surprise to spend part of my Virtuoso credit on. My waiter even had toured the winery in Northern Italy. Overall a very nice luxury property at a slightly lower price point than the top level properties in TYO.
I wouldn't hesitate to go back. I also like the relaxing location right next to Imperial Gardens. It is in walking distance to Aman Tokyo (where I stayed afterwards) and Tokyo Station.