Cerebro: This tool performs a reverse ASIN lookup, allowing you to see which keywords are driving traffic to your competitors' products. By entering a competitor's ASIN, Cerebro provides a comprehensive list of keywords that the competitor ranks for, along with metrics like search volume, relevancy, and competition. This helps you understand which keywords are effective for similar products and allows you to optimize your own listings accordingly.
Magnet: Magnet is a keyword generation tool that starts with a seed keyword you provide. It generates a broad list of related keywords, offering new opportunities that you might not have considered. Magnet focuses on keyword discovery, helping you find additional keywords to target in your listings and PPC campaigns.
In short, Cerebro is used to analyze competitors' keyword strategies, while Magnet is used to discover new keyword opportunities.