Microsoft plans to release DirectX 12 with Windows 10 on launch. So anyone who is in the DirectX 12 Early Access program is encouraged to also join the Windows Insider Program. Microsoft wants to have the most feedback from their developers on DirectX 12 to optimize their performance before launch.
There is also a new version of Unreal Engine 4.4 which has been ported to DX12; this port can be downloaded and tested by developers in the early access program. Microsoft also has mentioned they are working closely with Intel to deliver great DX12 performance on their integrated graphics. Integrated graphics are typical of laptops for better battery life, so hopefully DX12 will further increase the efficiency of those devices without compromise. Intel is providing sample test demos to all developers in the early access program.