As a SF resident, I can confidently say there is only one requirement they city should care about: people digging through the cans. No one gives two hoots if the cans are attractive (the current green ones are unsexy and unobtrusive which is fine). The issue is garbage goes in, and garbage gets pulled back out, before they are picked up. For every overflowing trashcan there are 5 that have been dumped by someone looking for food scraps or cans. At lest the people digging for cans tends to more respectful.