I've stayed here at least a dozen times before, and stayed here again for four nights on my first visit to London in four years. I love this place. The rooms are fairly large for London and I've always found them very comfortable. The soundproofing is very well done -- though the windows in my room open to the lobby and its atrium, which faces very busy Cromwell Road, I never heard even a whisper of noise. The breakfast buffet is good and I found the staff very friendly and helpful.
The location is hard to beat. The hotel is a 10-minute walk from the Natural History Museum, Science Museum, and Victoria and Albert Museum. It's a few minutes walk from the Gloucester Road Tube station on the Picadilly Line, which makes it very easy to get here from Heathrow (no change of trains needed) and to get anywhere in London.
You can walk to dozens of restaurants off Gloucester Road or Earl's Court Road. There's also a large Sainsbury's grocery store across the street.