IMO the aluminum ones are tougher, never seen shrapnel come right through it like the carbon fiber ones occasionally do.I think the CF ones cover more area though. If you do buy an aluminum one be careful of TCI (Total Crap Incorporated) as I bought one from them and never took it out of the box for 6 months. When I did I found the holes were all drilled in the wrong place and they told me to go pound sand.I believe they can be recerted on condition they are in perfect shape. No alterations,abrasions,oblong holes, etc.