It's all personal preference but you can't discount that Sunstar makes more spockets than anyone in the world. Or that Renthal has been around since I was born. They make products out of superior materials and they know how to manufacture them. Of course steel will last the longest. I just find when it's time to change my rear Aluminum Sprocket my chain is about done anyway. If I was concerned with max strength and longevity I would run steel and a 530. But like my sticky Bridgstone R11's I am choosing performance.