Spider Shade and Dirty Dog
I have used both the Sipder Shade and the Dirty Dog 4x4 shade, and the both work great. I like the Dirty just a little better because it's in 2 parts, so I can leave the back on if the kids still want shade.
Both shades do a good job blocking out sun. I went with a shade over a soild top because I wanted move air flow then a soild top gives. I know some people say that their soild tops trap in heat. I have also gone splashing through puddles and streams with both tops on, and while they still let water come through we got about 1/2 as we did going across the same spots without any shade or top.