1) The document proposes a new method to analyze relationships between substitute products using user browsing and purchase behavior data from e-commerce sites. It examines which products are superior to others in attractiveness. 2) The method was tested on wedding venue data from a Japanese wedding planning site. It accurately identified competitive and win-lose relationships between venues based on correlations with user survey data. 3) The method also extracts keywords explaining why one product is superior by analyzing reviews from users who chose that product over others. This provided more accurate superiority factors than a simple baseline method.