I had 3/8" HDPE backed with 1/8" ****ty steel skid plates on my 7,600# Tundra and they probably saw more action than most will ever see and never failed me.....blanket statement is blanket.....6061-T6 Aluminum in 1/4 is stronger than 3/16ths steel, and will hold up better to abuse. so 1/4" 6061-T6 skid plates are significantly superior than the ****ty 1/8th inch steel skid plates you guys think are stronger on rocks. is the aluminum worth the additional cost? up to you to decide, but the ALU is much stronger in that thickness and less prone to bending.
that said, aluminum will gall on rocks. A LOT. where as steel will just kind of slide over because its 'slicker'. the way around this is to attach cutting board plastic to the bottom of aluminum skid plates. 3/16th is more than enough and is much slicker than steel, and replaceable. this is common practice in rock racing.