Well Windows 10 should arrive on 12th January who is going to upgrade? I believe that the latest version of insider build is closest to the official stable build so how is it running? Never tried any of them though still on 8.1 which is pretty good for me but sometimes apps closes on its own which can be annoying. Feel free to comment current insider build here (advantages and bugs) and also this could be thread for W10 Mobile stable build when it arrives