Coincidentally i was looking at them a couple of weekends ago, they look very good, i thought as well, too good to be true.
I was tempted to buy one there and then but being the internet scourer that i am i thought i would research them first, i was shocked to see that not many people have much good to say about them.
common problems include tearing at the top where it slips into the bag, a lack of water proofing especially at the seams and apparently poor customer service when you ask for help.
i decided to go with the porchlite xl instead and although i have not tested it in the rain it went up very nicely and fast, i also dont like the thought of that big bag hanging on the awning rail.
oh yeah, the other issue was the bag flapping on the roof of the van in the wind.
dont want to turn you off them as i have had no first hand experience but my research did not turn up in their favour.