Of the options you mention, I would definitely go with the Hilton. All 3 are within about 10 minutes walking distance of each other, all fairly central in Miraflores. The Courtyard is good, and the staff are super friendly, but definitely a more budget option without the Executive Floor frills you get at the Hilton. Also, while the ground floor of the Hilton building hosts a row of nice restaurants, the Courtyard is on a more utilitarian block close to public transportation bus stops, etc. The location of the AC is good, about a block from the Malecon and Parque de Amor, but if you really want a deluxe Marriott option you would be better off with the JW Marriott a few blocks away and across from the Larcomar shopping center.