I find the Bitwarden extension is very good. The advantage of using an independent password store is that you can use it on other platforms. For example, Bitwarden provides iOS integration which provides autofill in both Safari and even within individual apps (which is a huge time-saver). In the future you may move to a different browser, and Bitwarden (or your independent password manager of choice) will most likely have an extension for that browser too so you can start using it straight away. I love Firefox but I honestly can't see any reason to lock myself into its password store.