Nice Hotel, Concierge Staff Not to Marriott Standards
The Mayflower is really a beautiful hotel but there are a couple things that definitely detract from the experience. 
PROS: 
Location is near great dining, shopping and attractions
Rooms are spacious and vary, no cookie cutters.
This hotel has fantastic history
Lobby and common areas are gorgeous!
Housekeeping was adequate if not great.
Front desk staff are very friendly.
Aveda toiletries
Comfortable mattress/pillows
CONS:
The hotel is huge, and often I had the feeling that I was in a deserted place walking down the hallway to my room.
I'm a Platinum Marriott Rewards member which allows me concierge lounge access. I found the gentleman who works the lounge in the evening inhospitable. He often followed myself and colleague as if he expected us to take an extra drink or a few too many nuts. One evening we came back from dinner and stopped in around 945 (they close at 10) and he immediately started clearing all the alcohol and food away as soon as he saw us. I can tell you that at the JW if we swing in before closing even if they are cleaning up they welcome us and ask what else they can get us. We are mostly small businesswomen who drink maybe a single drink so I'm not sure what his deal was but it really made me not want to go there at all.