We have used this service every time we have flown Virgin and I highly recommend it. It means you can get rid of your cases early on the last day and have more of the day to do whatever you want.
The actual check in area is located facing the car park at Cirque de Soleil in Disney Downtown. It consists of a canopied area and a long check in desk. Park your car opposite and walk over with your cases and join the queue (which is usually quite small if you are early). Everyone travelling with you must be present and you will need your passports and tickets, after all this is effectively the same as checking in at the airport and you leave here with your boarding cards, ready for the plane that evening.
You will have the usual security check first (has anyone asked you to carry anything for them, have you packed the cases yourself etc) then you will be called to the desk to complete the formalities. Once there you can also request particular seats if you want them, and if they have not been allocated, you should have no trouble getting them.
The service costs $5 per passenger and in my opinion the extra time it gives you is worth this small expense.
If you are staying in a villa, check if you can stay after the normal departure time, if there is not another guest arriving that day you can normally leave later allowing a leisurely last day. If you have children why not spend the last day at one of the parks, you can get them exhausted and hopefully by the time you get to the airport they will be ready to sleep on the plane home. Or maybe some last minute shopping. If you are feeling in need of a relaxing day why not spend the last day at one of the water parks. Just keep your cossies in your hand luggage and hire towels at the water park, and put the damp costumes in a plastic ziploc bag for the journey home....
One thing to remember though is the time your car must be returned by. If you go over this you may well find yourself charged any extra day so it is definitely worth considering if you want to use Downtown check in BEFORE you travel out and booking the car hire for the extra few hours initially. Even if you then don't use it, you are safe that you won't go over your allocated return time.
You arrive at the airport hopefully ready for a long sleep on the return journey, having had what feels like an extra day’s holiday.
Downtown check in is available from 8am to 1pm, but the earlier you get there, the more time you have to enjoy your last day. Try it once and you won't go back to long queues at the airport!!!