I had a camping lab awning that is about 99% the same as the ARB. it was about $200.00 and worth every penny...Both are made in the same factory in china out of some pretty high quality materials.
Very robust, very easy to setup with one person, and like you said, it creates instant shade or a damn good rain cover, right next to your rig.
Definitely not a replacement for a quality easy up that can be placed anywhere, but for something that is tucked out of the way, weighs like 15lbs, can be converted into a bug-proof room by zipping on a few panels...it really can't be beat.
I'm going to get a stubby one for the back of my rig that will serve as a sun/rain cover when I'm tailgating or grilling/cooking out of the back of my rig...
Fernando at Camping Lab is good people, but then again ARB is quality too. Can't go wrong with either one.
BTW, the 79" one is about right for an XJ, with about a foot sticking past the windshield if you make it even with the rear hatch.
I just mounted mine with some homemade brackets on a set of thule bars. Easy-peasy...