It's OK if you don't expect much
I bought three of these after reading everyone's reviews.  I figured I could send back if it really was awful, but I live in a super hot place and any little bit could help.  My windows are not tinted and I have a lot of window visibility! It's absolutely true that the fans don't work if they are not in direct sun.  If your windows are at an angle that won't tip the solar panel to the sun, it won't work.  If you park in a spot that isn't directly east or west, it won't work.  It won't work mid-day, because the sun isn't directly on the panel.  I'm lucky, my windows are at a pretty good angle and my parking area at work is a north/south/east/west set up.  I put one fan on the driver side, and one on the passenger side, and the little fans plug away most of the day.  They don't create a lot of breeze, they don't "pull" any hot air out of the vehicle, but they do see to move the air around.  For me, the difference these two fans make is whether, when I get in my car after work, I can touch my steering wheel with out it being too hot to grip.  My air conditioner takes a while to get plugging away and without the fans it's awful, with the fans moving air around most of the day I don't feel suffocated by hot air until the car cools off.  So, no the fans aren't great but they can make a difference if the situation is just right.<br /><br />Also, nothing I read discussed that the fan comes with a rubber thing that fits on the window and takes up the gap between the top of the fan and the window's edge... in theory it should but it doesn't, so you need to drive with air whistling or put the rubber on the window with the fan each day.<br /><br />I already broke one, I rolled up the window too tight on accident... so I guess you could say they're kinda cheap construction, but that shouldn't be a surprise for the price you pay.
Rating: 3 stars