We stayed at the Ritz-Carlton in October 2018, as the last stop of a pretty long trip.
The hotel building is very nice, centrally located near the Red Square and many city's attractions.
The lobby buzzes with people most of the day, as it seems that the bar is a very popular place to meet...
The king room was comfortable, separate shower/tub (bathtub faucet leaked immensely). Convenient Nespresso machine, but housekeeping failed repeatedly to leave extra capsules and milk, and sometimes forgot to replace used cups... I had to ask for a new iron, as the one in the room didn't work.
Check in was OK, we had a light lunch at the bar while waiting for the room to be ready. Check out was slow (perhaps because it was 1 am in the morning...??) As we had reserved through Amex Platinum Travel Services, we were granted credit for food at the hotel, but they had forgotten to apply the credit on our account, so we had to go over the whole check out process again. Also, I realized once at home that they had forgotten to add the Marriott Rewards number I had provided at check in. It was later added, after contacting Marriott and the hotel manager directly.
The lady Concierge was helpful in arranging our transportation to the airport (at a fixed price, which the driver finally increased...). The other Concierge (male) didn't prove very helpful when asked for subway directions.
O2 lounge has an amazing view of Red Square and the Kremlin. We had a couple of drinks and light supper before going to the Bolshoi ballet. Food and service, average.
Breakfast was good, many options available.
Overall, we had a nice, comfortable stay, but I had expected certain details to be more taken care of at this category of hotel