Lumia 640 LTE Dual Sim - 10586.71 - 2 days - feedback
Battery Life - 10/10 - the phone is back on it's normal behavior, no heat ups, lasts whole day and more with moderate usage of Fb messenger/whatsapp. messaging, calls, 3 email accounts syncing, Wifi at home 4G / 3G whole day at office.
Stability - 9/10 less hiccups and freezing. happened to me twice for the past 2 days. other than that this is stable as it can be for a beta software
responsiveness - 9/10 - much snappier and less bugs & lags. had an occasional resuming screen, where I just backed and launched the app
overall - this release is stable on the 640 (which was released with Windows 10 in mind and sports moderate hardware)
Hope all you guys will have (some of you are already having) a great time with it!