Agree with MM.
First of all, they're durable. A couple of my Griswolds are ~ 100 yrs old. Mine will probably be around long after I'm gone.
They heat evenly, darn near without fail.
You can get them squealing hot without worry of ruining them. Some things I make in them require that, like my Righteous Ribeye post or Sam's Blackened Redfish. I'm not saying you can't do either recipe with something else, but the process is easier with cast iron.
They typically do not warp and you can reseason them, if needed.
Word to the wise from someone who has done it. Don't grab the handle with your bare hand when cooking. They do transfer heat well.
