The "Cons" of aluminum have been covered fairly well above (although I do think people are generally a bit too paranoid, myself included
).
Here are some "Pros"
-The best thing about an aluminum hull is not the hull. It is the
deck, house and the multitude of structures and
hardware that (hopefully) are welded (not through bolted) in place. This makes for a boat that is easy to keep dry down below (I'm talking bone-dry even in heavy weather) with no repetitive re-bedding of
hardware and no rotten/soggy
deck cores. Deck structures like bollards and
anchor rode attach points are often strong enough to support the weight of the entire boat. To me, aluminum as just the right combination of strength and lightness for
decks and houses.
-Above waterline aluminum does not need to be painted at all. This utilitarian look is an "acquired taste" but a good compromise would be to
paint only the non-skid areas and perhaps the hull topsides. Leave the edges of rails (paint easy to chip) and tangs that get hardware attached (most likely place for paint bubbling) bare.
-An aluminum hull can have standpipes instead of standard through hull fittings. Another no maintenance item.
-Aluminum boats typically have blown-in
insulation on the inside
everywhere. This makes for a very cozy and dry (no condensation)
interior (let's not talk about the fire hazard of some blown-in insulation).
-Very strong and permanent modifications and
repairs can be made fairly easily with normal
wood working tools and a welding machine. Amateurs (like me) should probably stay away from large below waterline
repairs.
-Aluminum (and steel) boats are free of the flexing at sea that other materials may have. No creaking cabinetry (internal hull framing provides endless places to attach interior). No doors that wont shut or stay closed.
Steve