aluminum... overall it comes out on top as a building material
I tend to view materials as useful for a particular application. Aluminum may be useful if you are particularly concerned about weight. It appears the application for this thread is a cruiser. Seems unlikely justification for aluminum.
Aluminum structures need careful testing to quantify their fatigue life. The Airline industry makes use of an incredible quantity of aluminum for wings, landing gear and body. And they characterize the fatigue strength and resulting life with sophisticated structual test systems than often contain 100s of actuators. Quite impressive test systems.
So do these aluminum boat manufacturers subject their hulls to similar fatigue tests? Probably not. These multi-channel test systems cost tens of millions of dollars. Well beyond the wallet of the boat builders.
We have all seen the fatigue cracks on masts and booms on sail boats. Many of us have small aluminum boats with numerous fatigue cracks in various load points. And some of us have seen aluminum hulls from older boats with numerous cracks.
Even with the incredibly careful testing the airline industry subjects their planes to, they have fatigue cracks in the structures. Careful inspections catch most problems before the plane falls out of the sky. The automotive manufacturers perform similar fatigue testing.
If weight is the major concern, yes you might like an aluminum hull.. but really.. a cruiser is hardly weight sensitive. On the contrary, the heavier boat will be invariably more comfortable which cruisers eventually learn.
Wood rots, steel rusts, aluminum cracks/corrodes, fiberglass coring fails. Each material comes out on top for some particular application.
Take your pick.. just understand the limitations..