Browser extensions are usually ranked by how useful and smooth they are in everyday browsing. The features include things like ad blocking, password management, productivity tools, security protection, customization options, and how well they integrate with browsers like Chrome, Firefox, or Edge. The pros and cons focus on things like performance impact (whether they slow down the browser), ease of installation, privacy concerns, pricing (free vs paid features), and user interface simplicity. For real-world usability, reviewers check how reliably the extension works during daily browsing, whether it improves speed or productivity, how often it updates, and if it stays stable across different websites. The best extensions are the ones that add real value without affecting browsing speed or security.