Sapphire bay is a great location. For one thing, there is some reasonably good snorkeling right off the beach.
All the accommodations at SB are in one of four condominiums: Sapphire House, Sapphire Bay Condominiums West (frequently called "Crystal Cove") Sapphire Village, and Sapphire Beach Resort and Marina. Needless to say, each has it's advantages and disadvantages.
Because all four are condominiums, each unit within the condominium is under the care of its owner, resulting in a wide spectrum of condition.
Although there are a few exceptions, most of the units rented directly by their owner (usually by VRBO and/or HomeAway, are in decent, or better, condition, and most owners are conscientious and treat their guests well.
Again, with exceptions, the owners of the units in terrible condition, employ various agents to rent and manage their properties.Aggravating this, the on-site agents often do not treat travelers well.
That is why STTResident suggested finding a condo on VRBO, where you can rent an "owner-direct" unit. I would just be sure that the unit has a bunch of good reviews on the VRBO/HA page and/or in the review section of TripAdvisor.
I'm not sure about what you meant in your last question, but VRBO and HomeAway are not free. It cost between approximately three-hundred and one-thousand dollars a year for an owner to list on each site. The more you pay, the closer the listing will be to the beginning of the list (supposedly).