When comparing prices, you must look beyond the surface. Prioritize profile thickness, typically ranging from 1.2mm to 2.0mm for residential use and 3.0mm+ for heavy-duty commercial applications. Ensure the use of 6063-T5 grade aluminium alloy for optimal structural integrity. Additionally, verify the thermal break technology (polyamide strips) which significantly impacts energy efficiency and price, and confirm the surface treatment quality, such as powder coating (60-80 microns) or anodizing, to ensure long-term corrosion resistance.