It doesn't get much of a mention in this thread but I just completed a very nice stay at the Imperial hotel.

For context I've stayed at many luxury hotels in Tokyo (Aman, Bulgari, PH, GH, Andaz, FS Otemachi) and thought the service level on the imperial floor to be on par with Aman and better than the Hyatt brands and much better than FS which I consider to be the worst of the group service wise.

I used LHW points transferred from Citi (which seem to get ~3 cpm value at this hotel) to book a Junior Suite on the Imperial Floor and was upgraded without prompting to the 1-bedroom deluxe suite. Free American breakfast is provided in two of their restaurants or room service (though the options are fairly limited). The room itself was a bit dated but it seemed recently refreshed with modern amenities such as tablets that you can order room service and make other requests. It felt less dated than the GH for example which I consider to be fine. The service and concierge were just impeccable. Housekeeping noticed when I went to breakfast and made up the room while I was gone.

The one annoyance that wasn't apparent when transferring citi pts to LHW is that there were substantial taxes charged on top of the points paid (around $150 a night + 44k citi points in late march when luxury hotels are quite expensive in the city), but I still found it to be a very good value for what I got.