I typically stay at higher class hotels in Tokyo, but had to get here for city overbooking. THe Celestine is not the fanciest hotel, Pool and Gym are absent, but rooms lack nothing compared to those I go to in 5 stars hotels (especially amenities). There's a fine lounge and personell is kind, with good, very good English (also the cleaning team, I found out).
The GrandRock restaurant deserves a special mention. Nice architecture, some less fancy details, but the chef displays excellent european selection. It's not the busiest in town, probably, but this restaurant deserves high ranking for food, dressings and service. I rarely am surprised by what is offered, but here I had two fully regenerating dinners.
To sum up: not the fanciest, but a safe, decent well located option.