The Piccadilly's location is superb. Everything else is average, at best. Being located on Shaftesbury avenue, in the middle of Soho, some city noise is expected. In our room on 2nd floor this noise was really noticeable, and to some I suspect this will be perceived as too noisy.
When on a city holiday I guess most of us spend the day out, and perhaps return to the hotel sometime in the afternoon to relax a bit before going out to diner. When I come back, I enjoy finding the room cleaned. To me that's a part of the hotel experience. During all our 4 nights room cleaning occurred between 4pm and 7pm, right around the time we were back in the room to relax.
As others have mentioned, the breakfast room is a joke. It sits 10-15 people. On one occasion we had to wait 10-15 minutes, just to get a table.
The hotel announces it has a spa. This was not in service, and seemed to have been out of service for quite some time.