All garden planters are made of a variety of materials. Some will suit your garden and planting needs and others not so much. Keep in mind when looking at your choices that you will need a planter that is large enough to support the plants growth. You don't want to have to repot in one growing season. Also, make sure that you have a drain hole. Even if you are planting cactus or succulents which don't need a lot of water you still don't want their roots to be sitting in standing water.
Clay: Clay pottery has been around for decades. They are the most healthiest materials because they breathe which is good for the plants roots. There are different qualities of clay like Italian, Mexican and Chinese. Some use powder products and others are harvested out of the ground. Clay will break down fast and are very fragile and easy to break. They also need to be watered more because they dry out faster. There are high fired clay's now that will wear as well as a glazed planter so look for those if possible.
Poly Resin: Lots of large sizes because they are poured into a mold to cure and don't know a kiln to be fired in. Lots of colors and attractive styles. Our commercial grade poly resin is super durable and guaranteed not to chip, warp, crack or fade over time. One bonus is the shipping, moving and storing of poly pottery. It's lightweight will nest easily and you can move them around on a whim.
Glazed Ceramic: Colorful with shiny and matte finishes, glazed pottery is know for it wonderful glazes and finishes. Durable enough to handle a heavy frost but not enough for below freezing temps. They are heavy and moderately expensive. When you need to add color to your garden or patio area then this is the way to go.
Concrete: Durable, attractive and affordable. There are good manufacturers and not so good one so be selective. It will all depend on the concrete mix that is used on how well they will wear. Lots of color choices, and optional drain hole choices. Obviously you want them placed where they will stay because moving them is not an option.
Metal: Lighter weight, durable but unless powder coated they will rust. Many like that rusty look and prefer it to a colored finish. Plastic liners will help insulate them and keep the roots from overheating during the summer months. They come large and extra large which comes in handy for commercial applications.
So, no matter what you choose try to find a material that will serve your needs.