Are you sure it's not the other way around? That is, the burners are scratching the softer aluminum, which is leaving streaks?

At any rate, stainless and cast iron would be better choices than aluminum for many reasons.

If your cookware is anodized aluminum and your burner grates are cast iron then you will certainly scratch the grates because anodzed aluminum is way, way harder than cast iron. Stainless steel is also harder than cast iron though not nearly as hard as anodzed aluminum. The advantage of cast iron grating is that it won't scratch your pans, unless they're copper or non-anodized aluminum. Your pans will scratch the grating but so what?