Largo Mar is fabulous. Though I live in part of Fort Lauderdale, I've stayed there several times. Our consortium had its annual meeting there for years. It is a great beach resort... very upscale... "toney" and a delight. It is definitely NOT for the "I can get it $10 less by bidding" crowd. If you want an elegant, off the beaten track resort, Largo Mar is it.
Also... it's beach has a remarkable view of the exit from PEV... so... if you stay there on Saturday, for a Sunday departure, you can walk out onto the beach or jetty rocks and watch a parade of Saturday departure ships as they sail out... about 5 pm or so.
It is close to the airport and, obviously, close to the Port. Just over the 17th Street Causeway Bridge, in a very secluded area.