Cast iron engines are way more durable than aluminum engines. They're a lot more tolerant of overheating than aluminum because of how heat affects cast iron. It will still damage them if allowed to overheat for any period of time, but momentary overheating cast iron doesn't warp it nearly as easily as aluminum. It also doesn't absorb heat nearly as quickly. Putting a cast iron skillet and an aluminum skillet on your stove with the same temperature will give you an idea on how they heat up. The cast iron takes much longer to heat up, but it retains the heat better once it's off.

Cast iron is also much more difficult to strip bolt and spark plug holes out of than aluminum. Cast iron is very hard, aluminum is extremely soft. 

The drawback of cast iron is its weight. The 3.0 Vulcan V6 in my 1999 Ford Ranger weighs around 350-400 pounds. It's an overhead valve, pushrod engine with cast iron heads and block. I can't find specifics, but the Duratec 3.0 that replaced it in Ford's lineup was an aluminum block and heads with cast iron cylinder liners. Aluminum weighs about 60% of the weight of cast iron, which means the engine weighs probably 250 pounds or so. 

To the point of overheating tolerance, the Vulcan V6 was originally designed by Ford to run for 5 minutes while overheating without causing damage to the engine. I don't know of an aluminum engine that can tolerate this kind of abuse. Heat further softens aluminum from how it is at room temperature, making it much easier to distort or burst gaskets that are made of the metal.

I can't think of any sedans that offer cast iron engines these days. I would guess that the 5.7L Hemi V8s in the Dodge Chargers are still cast iron, they're still old-school pushrod engines like my Vulcan, only they've been updated over the years for variable valve timing.