Recently got one for the 4Runner, and one for the wife's car. I like them. They roll up pretty easy, fit the window pretty good, and keep the worst of the sun off of the interior surfaces. As stated, it won't eliminate all heat, but the difference is in how the seats, steering wheel, and console lid/armrest only get warm when using the sunshade (instead of searing hot without).
I have one of those el cheapo fold up ones in my truck. It is really crappy compared to the heatshield... I'll be getting a heatshield for the truck soon.
To be fair though, I don't know anything about their longevity. Only had mine 3 or 4 weeks so far. I say this because when you roll them out, the edges almost seem purposely stiff to fit the opening and keep it in place. Not sure how long, or if this stiffness will break down. If it does, I could see keeping it in place becoming more difficult, especially on the 4Runner's more upright windshield.
