Nothing wrong with ACE's have seen them on our decompose granite and they do take the beating but as suicide has already said, you will lose ground clearance.
I am running Rockhards "normal" skids, pricey yes but out here cheap isn't always the best solution.
Here is a rockhard version that is not so pricey and doesn't sacrifice ground clearance.
Rock Hard 4x4 Tube Style Rocker Guards - 4 Door 2007-2013 JK (pair)
Yep, they look like rubi rails that have been welded on.
Don't know your style of wheeling mild or wild but my advice is to save your pennies and buy better units such as PSC or Rockhard.
As for aluminum, on the slick rock they do pretty good but on anything else that aluminum gets chewed and dented up pretty good. We wheeled with a guy that HAD an aluminum belly pan. Emphasis on HAD... by the end of the run it was chewed and beaten up where the steel ones had a few scratches.