I'm on .242 on my 1020, and it's working very smoothly. Those who have .318, is that Fast Ring? I decided to go cautious and use Release Preview only as, it's my "daily driver". Does .318 fix the issue with recording video in mono only on the 1020? See the recent allaboutwindowsphone article on the reasons not to upgrade the 1020 to Windows 10. They include the glance screen not moving around the screen, creating potential burn-in issues (on builds prior to .242 I didn't have this issue; on .242, I notice that it does quite often get stuck in the bottom position, but sometimes it does what it's supposed to do, so buggy). Mr Litchfield also did some timings on .242 as against 8.1 Update 1, and reckons it takes nearly 60% longer to open most apps and other functions on the phone. Having said all that, I can't see myself easily going back to 8.1. The new Outlook is the killer app for me. Can't live without it. Ability to open virtually all Office documents, even password protected, is also indispensable. I'd only go back to 8.1 on this phone if I got a new daily driver and decided to keep this as a dedicated camera and (maybe) navigation device.