I second that opinion. We stayed for 5 nights last summer and had a fantastic stay. The pool and fitness club has an unbelievable view of Tokyo. The manager is very efficient but we had a few issues with the concierge staff giving us incorrect directions. They made up for it by giving us a free dinner in the New York Grill (a must). You must try a steak there, but be prepared to pay $100 a head (minimum).
They have a shuttle to the subway station that runs until 8 pm. They also got us reservations and special treatment at Chef Sakhai's french restaurant (for you Iron Chef fans).
Service is impeccable, rooms beautiful, you will have a great time! Unfortunately, since they are a Park Hyatt, they do not have a RC, so breakfast must be bought.