We've just discovered the show here in the UK and we love it. David's personality makes the show what it is, he's so positive and enthusiastic.
After binge watching we noticed the format is formulaic.
Also when you see the house buyers in the house they chose at the end of the show there are many items in the house that were there before, like hand cleaner and tea towels in the kitchen. So either it's their house anyway or to save the film crew coming back 3 months etc later they film the people in their house of choice why still on set and a pretence of family and friends coming around.