Go with the aluminum if you can afford it.
Galvanized steel is meant for the outside weather, and is better than aluminum itself.
Aluminum does not rust.
Each of them is better than the other for certain purposes and worse for others.
Galvanized Steel Swimming Pools are superior to polymer swimming pools because they are stronger, have more options regarding costummizations, they have a longer life spam, etc. The only, let's say negative thing about galvanized steel swimming pools is that they are harder to install.
It depends on what you want to do with it. Galvanisation usually involves zinc anyway.
Aluminum is not the best material for a garden trowel, while very light, it is too soft. A better material would be steel or even better stainless steel.
Aluminum is a better material. It will not rust like a steel resin pool. It can also be recycled when the pool is no longer usable.
I'd say the better heat convserver of the two, would be aluminum foil.
Inground vinyl is better, their is less exposed part to the oxigene, therefore, last longer.
Stainless steel is much better than galvanized for use as a zip-line.
Galvanized steel is better for plumbing in a bathroom sink. It lasts a lot longer than PVC.