What material lasts longest for an outdoor dining set?

Across specialist communities (notably r/BuyItForLife and r/homeowners) and mainstream patio-furniture testing coverage, the consensus favors HDPE/HIPS recycled-plastic composites and powder-coated or cast aluminum. Reviewers repeatedly report these resist fading, cracking and rust for years, while acacia wood and webbed/textilene seating tend to degrade faster under sun and rain.