Build 10240 is the RTM build so that's the final version. You can download it now.
Not officially I think. I was on 10162 and updated through that to 10240. I had a look on the insider site to see if I could download the ISO for 10240 and MS have removed the downloads page and say they aren't 'onboarding any new PC's' so close to the release date although you can still update any PC's already set up on the insider program, whatever that means.
I had concerns about transfer of licences and activation but the EULA for 10240 (you can find it by searching for/running the command
winver) looks the same as Windows 8.1 in that regard ie if your underlying licence for win 7/8.1 is transferable then the free upgrade to 10 is as well. And it appears that there will be a 10-year support cycle for W10 as for previous windows versions:
http://www.maximumpc.com/microsoft-addresses-windows-10-subscription-fears-with-10-year-support-commitment/although it's only officially supported if it's fully updated. Not something that is relevant to Home users as they'll be getting updates whether they like it or not. Pro users can delay updates by up to 8 months, any longer than that and they stop receiving them and the installation stops being supported. Also, "supported for the lifetime of the device" appears to mean that if your W10 installation is on an old PC/Tablet or whatever, and a future upgrade breaks the OS because of a lack of old hardware support, then you're screwed. BUT as long as it's not OEM/preinstalled then you should be able to transfer the licence to another device instead. I think.
Anyway, Windows 10 itself is really very good. I'm running it on an old Athlon 64 X2 5200+ (2.6GHz dual core)/2GB RAM build and it absolutely pisses on Win 7. A few UI annoyances (
slightly blurry text due to the old barely-supported video card) and e-mails that I've already read and deleted still appearing in the notification centre and the like (that may be because I read my outlook emails through chrome and not through the MS mail app) but I reckon 10 is continuing the microsoft good/shite OS cycle.