Stayed for one night to attend a western-japanese wedding.
First of all, transportation to the hotel is very very convenient, as it sits next to the Daiba overground station (this is a relatively new line and even just the ride is worth it!) - we thought of taking a taxi but in the end it was easier and cheaper to travel by tube.
Rooms are pretty average European style (later found out that we had a very large room by Tokyo standards), nicely equipped bathroom (both extremely clean). Very nice views of Tokyo bay.
We arrived at 11am and were able to check-in by paying a 5,000Y supplement.
It looks like this hotel has made a speciality of weddings, with chapels, waiting rooms, and reception rooms. It was all very nicely organized and timed with the usual impeccable japanese service.
We did not try any of the restaurants due to the short stay, but if the wedding reception is a measure of the French restaurant here, it must be very good (and we are French!!), absolutely fantastic creative, light dishes with a Japanese twist. Desserts were absolutely excellent.
The hotel is very very big with large halls and hallways, escalators, and feels a bit overwhelming and impersonal. In addition to wedding parties, it seemed quite full of families.