Adelaide pergolas typically use Colorbond, timber slats, or insulated sandwich panel. Here's the honest comparison.
Colorbond (most popular)
~$95-$140 per m2 installed. 15-year manufacturer warranty (12 coastal). Standard choice for attached pergolas/verandahs. Cons: radiates heat in summer.
Insulated sandwich panel
~$180-$280 per m2 installed. 15-25 year warranty. Drops alfresco temperature 15-20 degrees vs Colorbond. Best year-round comfort. Cons: 25-40% more expensive.
Timber slats (open-roof pergola)
~$150-$220 per m2 installed. Decorative, lets air through. Suits low-rain areas, climbing plants. Cons: minimal rain protection, more maintenance.