Aluminum anode rod is better than the magnesium anode rod. It’s better for the water that contains a higher pH level.  It withstands the hard water better than any other types of rod like magnesium. The aluminum rod is less reactive than magnesium rod and prevents the tank from corroding.  Most importantly, the aluminum anode rod will not cause rotten egg smell in water like the magnesium anode rod does.  Turns out, the aluminum rod lasts longer compared to the magnesium one. However, the aluminum rod will deplete faster than normal if you use a water softener.  In short, aluminum anode rod is better than the magnesium one because of the sense of ability to handle hot water, longevity, and the price.