I’d say Taj. The Taj Mahal Palace & Tower in Mumbai has unique history. This is one of the gracious landmarks of the city. Excellent hotel with the outstanding service. Worth to upgrade to the club rooms as you get a private breakfast room and a very spacious room. And if are planning to wonder around I can recommend you an upscale tour operator Orientflexipax, offering private luxury tours in India. You can also take their advise on a hotel and book it through them.