We've stayed in 2 properties managed by AllStarVacationHomes at Windsor Hills and both were really nice. They cost a little more than going through a private owner, but we were really impressed with the quality of the furnishings and the service from AllStar. I don't think you could go wrong with any of their properties.
This year, we booked with Storytime because the kids wanted a place with a little more Disney theming. The funny thing is that our townhouse this year is right next door to the one we stayed in last year. We leave on Monday for our trip, so I'm really looking forward to seeing our new home for the first time.