Wrought Iron
Iron furniture is extremely durable structurally and holds up well against North Texas wind and storms, but its main vulnerability is rust once the protective coating is chipped and humidity gets in. Regular cleaning and prompt touch-up of chips is the key maintenance need.
Aluminum
Aluminum won't rust the way iron does, making it lower-maintenance in that specific regard, but it can pit or corrode with white powdery oxidation if left uncleaned for long periods, especially given DFW's humidity.
Wicker and Resin Wicker
Natural wicker breaks down relatively quickly under sustained sun and humidity cycles. Synthetic resin wicker holds up much better but still needs regular pollen and dust removal from its woven texture.