sorry to bump an old thread here, but I have a Hefty rear and skids en route so I'm reading up where I can....
the point about aluminum skids that I think everyone is missing here so far is that because of the relative softness of aluminum, they might not be the best choice where you want to slide over obstacles (ie. rocks). the comparison was made to aluminum wheels, and how they hold up after hitting rocks etc (or curbs in your wife's case), my wheels have had several good contacts with rocks while wheeling, and the result has always been the same: a jagged gash. looking at my sliders, or even the low quality ARB skids, or the stock tin foil gas tank skid - all of which have taken significant abuse - there certainly are large scratches from being dragged over rocks (dents in the case of the arb's and tank skid) but the damage is superficial due to the hardness of the material. it may be heavier, but steel will side whereas aluminum grabs.
So if all you plan to encounter are tree roots and dirt, by all means go aluminum. But if you see water crossings and rocks, suck it up and get the steel. It's not as if these things are a huge issue to put on and take off if you are concerned about weight on a daily driver.
