No real disadvantage. Durability shouldn't be a problem unless you make a habit of tossing your equipment across the brew room. If you go weld-less, it should be easier to drill a hole in aluminum, any of the weld-less ball valves kits you might find on the internet should work, just remember not to over tighten and distort the o-ring/gasket, over tightening it is probably the biggest culprit in terms of leaks.
A couple years ago (IIRC) BYO had an article (although darned if I can find it in their story index) where they did a blind tasting of the same beer brewed in both aluminum and stainless steel, no one could reliably tell by taste which was which. Most people will only "taste" aluminum flavor in a beer if they know beforehand the it was brewed in aluminum.
