Cast iron is great too though, don't get me wrong.
https://en.wikipedia.org/wiki/Aluminium#Health_concerns
These guys recommend stainless or cast Fe. http://whfoods.org/genpage.php?tname=dailytip&dbid=92
Aluminum yes, but hard anodized is alumina which is a different compound, also called ruby and emerald. It's very very hard (as you can tell since it makes gemstones) and completely inert to cooking materials.
Confusing aluminum and hard anodized is like confusing chlorine and table salt.
Not only does the hard anodized surface work well, the lids have small holes where the spout of the pan is so that you don't need to use a colander.