They look really well made and worth the price.
I was also concerned about corrosion but others have reported no issues. I plan on using blue locktite and prepping the bottom of the pinch weld with an undercoating (will just brush on sparingly). I like the idea of adding an aluminum shim, as that would take some of the slop out.
I can look under the car and see the spot just fine, but I have a base 1SS and the lack of side rocker panels improves visibility.