I have to disagree with one thing he said, and that is that a 270 degree awning is not great if you are going to leave your rig in one position the whole trip.
When I used my Eezi-Awn Bat 270 awning at Mount Rainier last August, I did not move the rig, and I had very good protection from the sun the whole time.

 

I want to fit a retractable awning at the back of the van, so that it creates a nice outdoor area between the rear barn doors for cooking under etc.