Seems overrated as a "luxury" hotel. Let's start with the good:
1. Mayfair is a nice area overall and you can walk from the hotel to several coffee shops and a Shepherd's Lane area with many small restaurants around the corner.
2. Green Park and its tube station are only a couple of blocks away
3. Porters were generally agreeable
4. Hotel is clean and seems to be popular with international guests
Now the drawbacks:
1. Small rooms (not that unusual for London) with VERY THIN WALLS. This was a major detractor for me.
2. Bathroom privacy was concerning as the window has a thin curtain that does not blackout visibility and I do not believe windows are tinted. If I were female I'd be concerned taking a shower.
3. The shower/tub lacks a full door so water gets on the ground of the bathroom very easily.
4. No dental kit or other typical bathroom amenities. In contrast, I stayed another night and previously for a week at another hotel on Leicester Square that had great amenities.
5. No in-room guide to tell you if there even IS in-room dining
6. Not sure if there is a gym but no pool/spa that I can tell, or if so, no evidence of marketing it to the guests
7. As nice as Mayfair generally is as an area, this hotel is not actually near any department stores, boutiques, grocery stores, etc. It's a considerable walk over to Regent Street for older travelers or families with young kids (I would NOT recommend this hotel to such families, as the rooms are too small and walls too thin).