I adore the Four Seasons at Hyde Park Corner for comfort, style, service and location. The conservatory rooms are spacious and full of natural light. The lobby bar and formal bar are full of life. Food is sumptuous. But, alas, no frequent stay or frequent flyer points. The parks are literally across the street. Belgravia, Harrods, Regents Street, theater district and royal/government buildings are all easily walkable in fair weather. On my last November visit, temperatures were in the 60s.