The fast fashion market is projected to grow significantly from 2023 to 2030, driven by increasing demand from a youthful demographic. A study analyzing customer sentiment on Trustpilot for five prominent fast fashion brands—Boohoo, Wish, Shein, Fashion Nova, and Temu—reveals insights into product quality, customer service, value for money, and eco-friendliness. The analysis shows a predominantly positive perception of these brands, with product quality and affordability being crucial factors. While innerwear and swimsuits are particularly well-received, dresses and outerwear evoke varied responses. Customers appreciate one-time wear items for special occasions, often citing quick delivery and good customer service as important. There is an opportunity for brands to improve sustainability efforts, as most customers currently appear indifferent to eco-friendliness. The study underscores the importance of high-quality data for precise customer sentiment analysis and highlights Bright Data's role in facilitating comprehensive data collection for such research.