Tested Windows Mobile 10 on my Lumia 640XL
Disappointed as it fail to even detect my Samsung 128 GB Card. Took out the card and reinsert/restart phone still same issue
I than plug in a 64 GB Sandisk and card is now detected but apps just failed to install onto the ext sdcard
Now reverted fully back to 8.1
Hope the official version will not have such issues
The WM10 however does indeed looks more polished and classier

I had decided to upgrade again my 640XL to Windows 10. The previous time , it failed to detect my 128GB ext Sdcard
This time it was successfully done and apps restored back but than I noticed about 1GB of app was installed onto internal memory while another 1GB was at ext sdcard. Took some time ( darn slow) moving most of the apps back to ext Sdcard

my OS build is 10.0.10572.0

This 640XL is my 2nd windows phone after Nokia 1520. Frankly Windows app quality had a long, long, long way to go vs Android and even worse if compared with IOS. I don't see any significant changes and improvements vs my ex Nokia 1520 about 2 years ago !

Updated my 640XL to 10581 build but yet to see any obvious improvement

Official version is not even released yet!!

I had signed up and already received my entry ticket

I had installed several builds of Windows 10 on my 640xl ( on latest 10586 now). Midway I had tested n successfully downgraded back to 8.1 through their restore tool
Probably the 640xl specs is too weak for Windows 10 . There is obvious lag n slight stuttering in use
Again windows app still remain very poor quality vs Android n IOS. Those who had never use android n ios could happily accept what windows is offering ??

This post has been edited by benny888: Dec 7 2015, 04:28 PM

Just updated my 640XL to 10586.36 - noted immediately previous slight stuttering had improved