What are my options for upgrading to Windows 10?

Wipe and load - This is the traditional approach that many organizations use. A tool, such as System Center Configuration Manager and/or Microsoft Deployment Toolkit, captures the current data and settings of the current operating system. Then a new image is deployed to the machine, drivers are injected and applications installed. Finally, the user data and settings are restored. This gives users the feeling of an upgrade, while what actually happened was a clean installation. 

In-place upgrade - This has been frowned upon in previous versions of Windows, but with Windows 10, the in-place upgrade is now a first class deployment option, and is now the preferred approach for Windows 10 deployment - even in enterprises. It allows Windows 10 installations to be initiated from within the existing Windows 7 or above OS. Behind the scenes the setup.exe is doing a very similar process to the wipe-and-load. However, setup.exe is doing all the work and maintains all settings, data and applications -- basically, anything that is not part of the old version of Windows is kept. Enterprise management tools like System Center Configuration Manager will support the in-place upgrade approach for Windows 10 through a new Task Sequence step, Upgrade Operating System. 

Provisioning - For new devices that have an OEM Windows 10 image, it will be possible to ship the out-of-the-box Windows 10 device direct to a user and have the deployment transform into an Enterprise SKU, then add organizational apps and configurations while removing extra things not required — and there's no need to wipe the device. This process will take around 5 minutes. This is enabled through a provisioning package (ppkg file) which performs all the tasks and reboots the machine. When the device restarts it will be running the Enterprise edition. These provisioning packages will be created with a new tool, the Windows Imaging and Configuration Designer (Windows ICD). The Windows ICD tool is part of the Windows Assessment and Deployment Kit (ADK) — which allows all your chosen settings, profiles and applications to be turned into the Provisioning Package file. The Provisioning Packages can be deployed using many methods, including using the new MDM Client in the OS from a MDM Server and from Microsoft Deployment Toolkit/System Center Configuration Manager. If you do use the provisioning approach, all the drivers on the machine are kept. This is a net benefit for admins, because it's easier to support users picking their own devices.