I think it depends on how high the awning is mounted above the slide. My folks have this on their 5th wheel for a slide holding their booth. The awning isn't much above the slide-out, and they have problems with water pooling as they can't get enough slope to drain. Also, lots of the awning room outside is taken up by their slide. I don't like it and specifically looked to avoid a layout like theirs on our new 5er.
2003 GMC Serria 2500HD D/A
2016 Jayco 355MBQS