I have used skyauction for our 3 previous trips, and have friends who have used them successfully as well.
We use the ready, set, go auctions (go to search, and type in keyword "ready", and then you can select one of the current auctions. They usually have 3 going at a time) On our 3 trips we won our auctions for $52, $52, and $67 respectively, and then you add the service + admin fee of $210.00 so the most we paid was $277. for the week in a 2bdrm condo. We have stayed at Cypress Point Grand Villas, Bryan's Spanish Cove, and Orbit One. All were very nice and clean, but we liked Cypress Point the best.
Since then, they have increased the fee to $295 + $15. so $310 total, plus whatever amount you pay for the auction. Still an awesome deal. We aren't using skyauction this time because I need in room internet available to be able to stay in contact with clients if necessary, so we have chosen to rent directly from an owner at Windsor Hills. Also, the skyauction rentals are for 7 days and we are staying for 9 days, so we would either have to stay elsewhere for the extra nights or pay whatever the resort wanted to charge us to book directly through them to not have to move hotels during our stay.
If we were only staying 7 days I wouldn't hesitate to use skyauction for a 4th time.