Are metal or plastic travel pill organizers better?

It depends on priorities. Plastic models like the AUVON line are lighter, cheaper, and tend to have the largest review bases, while aluminum-alloy boxes with gaskets are favored by buyers who want a more sealed, moisture-resistant feel for travel. Note that 'waterproof' is a manufacturer claim here; verified-purchase reviews generally support water resistance but few independent tests were available in our data.