The four interior shooting approaches Mike compares are:
Mike does a good job of illustrating the strengths and weaknesses of each of these shooting approaches.
Mike's article shows that Multiple off-camera flashes give the best looking results and the other techniques can create be used while you are building your competence and confidence with the multiple off-camera flash technique.
Regular readers may recall that back in June of 2011 I polled readers on these and related shooting approaches in this post. If you look at the poll in this post carefully you'll notice a couple of interesting things:
So even though Mike shows it's clear which technique gives the best results real estate shooters are using a variety of techniques.