I have just wrapped up my second trip (part business/part fun) to the Key Largo Bay Marriott Beach Resort. It is a quiet property with a nice pool area, unique and small beach set up and merely adequate guest rooms. Your room door will open to the outdoors, it is worth noting.
If you are seeking a simple get away and do not want to be amongst the fuss of South Beach then this is a nice destination after leaving MIA. You will find the beds to be comfortable, the food and drinks to be better than average and the wait staff to be mostly engaged. We will revisit this property at some point to be sure.