LastPass is a great and secure way to generate and store passwords. HOWEVER, the browser extension (for both Firefox and Chrome) is often unusable. It is slow to sync and frequently just fails to load. It also saves more passwords than it should (which cannot be disabled in options). Sometimes, it also repeatedly generates the same password with it's "Generate Secure Password" feature, which is a security nightmare. I recommend LastPass and the mobile app, but I highly discourage the use of this extension until the serious bugs are addressed.