That's a great question I've actually wondered about myself, especially after seeing both types around my neighborhood. From my experience and what I've gathered, stainless steel urban trash cans do have a clear edge when it comes to ease of cleaning, but it's not a simple black-and-white answer.
The biggest advantage of stainless steel is its non-porous surface. Graffiti, stickers, dried-on spills, and general grime don't soak into the material. A good power wash or a wipe-down with a disinfectant usually brings it back to a shiny, like-new state. You don't have to worry about the cleaning process itself fading or damaging the finish. For city maintenance crews dealing with constant mess, this is a huge time-saver.
Colored trash cans, typically made from coated steel or plastic, can be trickier. Lighter colors show every smudge and dust streak, demanding more frequent cleaning to look presentable. Darker colors might hide dirt better initially but can fade and chalk under strong sun, making them look permanently dull. Scratches and scuffs on the colored coating are much more noticeable and can't be polished out, revealing a different color underneath and giving the bin a permanently worn look.
However, stainless steel isn't perfect. It shows water spots and fingerprints easily, and in some settings, its industrial look might be less desirable than a colored bin that blends into a park's aesthetic. Colored bins can also be made from materials that resist rust and are lighter to move.
So, for pure, long-term ease of maintenance and a consistently clean appearance with heavy public use, stainless steel is generally the winner. It forgives harsh cleaning and ages more gracefully. A colored bin might look perfect when first installed, but keeping it looking that way in an urban environment often requires more effort over its lifetime.