Glass globes offer the best reflective quality but they're fragile. They must be secured to a pedestal with double-sided tape to withstand a big blow. The ones with stems need be sealed to prevent moisture from entering, which will cause the finish on the inside to crack and flake. In below freezing winters, most sellers advise bringing them indoors. The stainless steel balls, or mirror balls as they're called, are durable and long-lasting.
Sellers claim that they never tarnish or rust or shatter.
They're highly polished but their colors appear dull, and they lack the reflective quality of glass globes. The inexpensive knockoffs offer color but no reflective quality. They're also likely to be as susceptible to high wind as glass ones. Glass and steel balls come in a wonderful range of colors, including silver, purple, green, blue, red, and gold. Some of those with a fancy finish may not be as reflective as solid colors.