Are stainless steel or ceramic fountains better than plastic?

Across the reviewers we read, both stainless steel and ceramic are preferred over plastic for hygiene reasons. Specialist-community threads on r/CatAdvice and r/Pets repeatedly note that plastic develops biofilm and is linked to feline chin acne, while steel and ceramic resist scum, are easier to scrub, and are often dishwasher-safe. Plastic models like the budget Veken remain popular mainly on price.