Does anyone know how the security of Firefox 57.x now compares with Chrome (and Edge)? As I understand it, FF is starting to sandbox things, but I doubt it is up to the level of Chrome, especially now that you can enable strict site isolation in Chrome (with some caveats). According to Google, the Strict Site Isolation feature puts "even stronger security boundaries between websites than Chrome’s existing sandboxing technology." Apparently, Google introduced this feature in response to Microsoft introducing Windows Defender Application Guard (WDAG), which allows Edge to be run in an isolated hardware environment. "In October, Microsoft said that WDAG marked a major breakthrough in sandbox technology since it offers a shield against attacks on the kernel, which is unprotected if an attack escapes the browser sandbox." I think hardware-based isolation would be the most secure, however, WDAG can only be enabled on Windows 10 Enterprise edition (fingers crossed it trickles down). So, it seems to me that Chrome is currently the most secure option that is widely available. Furthermore, with all of that new code in FF, security vulnerabilities are very likely.