I prefer cast iron for cooking on a fire - for bug in, but it isn't my choice for a bugout, they are just to heavy compared to the aluminum. Blacking the bottom of a pan is not the end of the world. I think people are too fixated on appearance of cookware more so than they should be on the usefulness of the cookware.
I've blacked up more than one aluminum pot and it still boils stuff just fine.
The stuff still works.
I do trust the cast iron more though for cooking as, metals like aluminum arn't really fully safe.
Things that are teflon coated are horrible so most nonstick stainless steel is incredibly unhealthy to cook with.
None the less I'm sure most normal people would cringe at the thought of turning a pot black, to me it really means absolutely nothing. It doesn't shine as much, big deal.
The stuff is not safe to cook with for a bugout. large ceramic mugs hold heat really well and won't crack if you put them in a fire, they do get black though. Most people arn't worried about getting metals into their body though. Overall iron stuff seems like some of the best.
IMO the alluvial metals are the best to use for cooking. But remember you can cook with earth or bark, leaves etc..