The best materials for pool ladders and steps are stainless steel, resin, and fiberglass. 
Stainless steel is highly durable and resistant to rust and corrosion, making it ideal for both saltwater and chlorinated pools. It offers a sleek, modern look and can withstand heavy use and harsh weather conditions. However, it can become hot under direct sunlight and may require regular maintenance to prevent tarnishing.
Resin is a popular choice due to its affordability, lightweight nature, and resistance to UV rays and chemicals. It does not corrode or rust, making it suitable for all types of pool environments. Resin ladders and steps are often designed with non-slip surfaces for added safety, but they may not be as durable as metal options over time.
Fiberglass is another excellent material, known for its strength and resistance to chemicals and UV exposure. It is lightweight, easy to install, and provides a smooth, non-abrasive surface that is gentle on the skin. Fiberglass is also resistant to algae growth, making it low-maintenance. However, it can be more expensive than other materials.
Each material has its advantages, and the choice depends on factors like budget, pool type, and personal preference.