Many multiple circumnavigators have metal boats and unfinished aluminum is a popular choice, particularly with Europeans. There is no question that a metal boat will survive more pounding on a reef if you

- US builders
- Size
- Resale
Size: Metal boats can be built faster and cheaper than fiberglass boats because they don't need a mold; they just cut out the pieces and start welding them together. This is an enormous savings on a larger boat and the economics of building a larger boat from metal are very compelling, but for a smaller boat, not so much.

The final size factor is the plating. According to Chuck Paine, he would have needed to specify thicker plating than was really structurally necessary to prevent "oil canning", or the flexing of the plates between the frames. The flexing is not a structural problem, but it is unsightly and at times unnerving. So I'd pay for thicker plating, and always haul the extra weight around. On a larger boat the plating would need to be thicker anyway so there was no issue.
Resale: Europeans like metal boats, but Americans are not so keen on them. Taking a boat to Europe to sell is tricky from a tax standpoint, not to mention that the buyer will expect 230vac internal wiring. The US market would be a tough market, meaning lower resale value.
A couple of horror stories also contributed to my decision. There are plenty of stories about metal boats that were poorly maintained and had a shortened life. But the same is true of fiberglass or wood boats, you have to do the maintenance. But I have personal knowledge of two boats that were built from defective aluminum. The build quality was fine, but the aluminum plating was flawed and had a shortened life. One of the boats had to be entirely scrapped within two years of being launched and the owner was left to fight with his insurance company and Alcoa. The other boat was sold for next to nothing after about ten years when the problem fully manifest itself.

But what about fiberglass? Fiberglass is a well understood boat building material with broad market acceptance. The resulting boat is lighter than either wood or aluminum and requires less maintenance. When I asked Cees van Tonegran what material he would use for a boat for himself, he said fiberglass.
As I said in the beginning, metal is the material of choice for many long term cruisers, but I concluded that fiberglass was the best material for the new boat.