This morning I got the prompt to upgrade my SP3 to Windows 10, and the upgrade process was very very smooth (good job MS).
However... once it was done, I get no wifi networks at all - in fact, it's almost like I don't have a wifi card, which obviously is impossible :)
I have tried pretty much all the suggestions available here (https://www.microsoft.com/surface/en-us/support/networking-and-connectivity/install-wireless-drivers?os=windows-8.1-update-1) and none worked. I downloaded the SurfacePro3_150623.zip file, went to Drivers\Network\WiFi and installed mrvlpcie8897.inf but no luck.
Device Manager reports my wifi adapter as a Marvell AVASTAR Wireless-AC Network Controller (which seems about right to me) but I still get nothing...