We first got the Prompt sunscreen last year because of the advertised ability to put up without a ladder. The demo video looked easy-yeah .
I provided lots of campground entertainment trying to put that thing up. When I finally did get it up it would sag. It did a fair job at what it was supposed to do but I didn't like the PIA factor and the look of the sag. Already have enough of that. So broke out the wallet and purchased snap on for windshield and all windows. Wallet went flat but the mh stayed much cooler. (We were in Las Vegas in summer). I also had awnings installed over most windows which probably made the most difference.
I find it takes me about 1/2 hour to install all shades (I'm getting pretty slow) and the only real downside is that it considerably darkens the inside. You have to go out to make sure it isn't going to rain! As others have said, you can see out (reasonably) during the day and others can see in (well) during the night if you have lights on.
Would I do it again? In a heart beat!