Are you putting it over the back door or on the side? I've got mine over the back door - works fine but in retrospect I would prefer to have it on the side so it could be on the body and not the roof. I think it would generate more usable shade being lower.
Curious to see what brands rise to the top - have a Fiamma and yes they are spendy. Wouldn't mind a 2nd cheaper one for the side.
-Vic