I've been using my Verizon 822 with W10m for about 6 months and recently even added a family member to the new OS. Since Verizon dumped MS I considered a 950 so I went to the ATT Store and saw it and the 640. Both impressed me on the $598 to $59 scale. A few days later MS Store had the 640 for $38 and I bought two. Upon receipt (it had W8.1) I immediately installed Insider Fast and it installed W10m, then off to the ATT Store for no contract service activation that costs less then Verizon. The Service rep was excellent and knowledgeable (thanks Calvin Cornet in Camarillo).
It has been a few days and I am really impress with the 640. My Nokia 822 was so sluggish and the 640 is very quick especially Edge, great battery life and camera is quick with really good photos in a variety of lighting conditions and video is good too. My only complain is the Glance/Recharge- Glance Always Visible mode. It is very hard to read at night without picking it up and looking right on axis to read it (the time) no matter which color is chosen vs. the 822. My experience.
It has been a few days and I am really impress with the 640. My Nokia 822 was so sluggish and the 640 is very quick especially Edge, great battery life and camera is quick with really good photos in a variety of lighting conditions and video is good too. My only complain is the Glance/Recharge- Glance Always Visible mode. It is very hard to read at night without picking it up and looking right on axis to read it (the time) no matter which color is chosen vs. the 822. My experience.