Which Eriba model is your van and what year is it?
The Kampa awning sits well with a "nice" fall on the roof for pre 2010 vans. If your van is post 2010 then it does appear to slope a lot as the awning rail is higher. If you use the search facility you will find a lot of discussion on this awning. To get to the point, on pre 2010 vans it is very good, on post 2010 vans you may have issues with the awning cord pulling out at the ends if you own a Troll and possibly on a Triton. On Familia and Puck no problems. Interestingly it looks like AL have now stopped selling the Kampa, or at least it is not on their website, just the AL Twin Air as an air awning is advertised.
The Twin Air is new out, and members seemed to like the look of it at AL when on display. It is about £300 more expensive. Others will give an idea if it is worth the extra as I have not seen one in the flesh.
Colin