That's a great question many city planners and property managers consider. From my experience, both materials have their place, but the "better" choice really depends on your specific priorities.
Metal trash cans, typically made from galvanized steel or aluminum, are champions of durability. They can withstand harsh weather, resist vandalism better, and are less likely to blow over in strong winds. Their weight is both an advantage for stability and a drawback for maintenance crews who have to move them. They also tend to have a more premium, permanent look that suits formal urban areas. However, they are more expensive upfront, can dent, and are prone to rust if the coating is damaged.
Plastic bins, often made from high-density polyethylene (HDPE), are the lightweight and cost-effective option. They're easy to clean, won't rust, and their initial purchase price is much lower. This makes them excellent for high-traffic areas where bins might need frequent relocation or replacement. The downside is they can become brittle and crack in extreme cold, may fade and look worn over time, and can be easier to tip over or damage.
For long-term, high-vandalism areas, metal often wins on lifespan. For budget-conscious projects or places needing flexibility, plastic is very practical. The ideal solution might even be a hybrid: a durable metal base with a plastic liner for easy servicing. Ultimately, it's about balancing durability, cost, aesthetics, and maintenance for your specific urban environment.