Windows 10 is great! As a typical Windows administrator, you might ask so what is new in the Group Policy? Well all the group policy is well documented at the link below: https://www.microsoft.com/en-us/download/details.aspx?id=25250 Download the file by selecting Window 10 ADMX spreadsheet. 
Open up the file, you can filter all the new to Windows 10 group policy through the last column
Here are three questions that came up quite a lot
DISABLE Cortana in Windows 10, via GPO or Regedit This is possible by editing below registry key HKLM\SOFTWARE\Policies\Microsoft\Windows\Windows Search!AllowCortana This policy setting specifies whether Cortana is allowed on the device. If you enable or don’t configure this setting Cortana will be allowed on the device. If you disable this setting Cortana will be turned off. When Cortana is off users will still be able to use search to find things on the device and on the Internet. DISABLE Windows Update Delivery Optimization (WUDO) in Windows 10 This is possible by editing below registry key HKLM\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization!DODownloadMode Set this policy to configure the use of Windows Update Delivery Optimization in downloads of Windows Apps and Updates. Available mode are: 0=disable 1=peers on same NAT only 2=Local Network / Private Peering (PCs in the same domain by default) 3= Internet Peering DISABLE WiFi-Sense in Windows 10 There is no GPO for this. Some organizations want to turn this option off as they may see this as a risk to corporate Wi-Fi. An enterprise can disable in the following ways:
- Configuring via the Windows Provisioning framework: https://msdn.microsoft.com/en-us/library/windows/hardware/mt219718(v=vs.85).aspx
- Configuring via legacy Unattend (if enterprises are using unattend for provisioning): https://msdn.microsoft.com/en-us/library/windows/hardware/mt186511(v=vs.85).aspx
- Use group policy to create (as a DWORD) and set the following regkey equal to 0: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WcmSvc\wifinetworkmanager\config\AutoConnectAllowedOEM
Using any of those policies to disable Wi-Fi Sense results in disabling all related features of Wi-Fi Sense: connect automatically to open hotspots, connect automatically to networks shared by my contacts, and allow users to share networks with their contacts.