Device compatibility list (Last updated August 3rd, 2013)
Sources
Surface Pro: Working.
Surface RT: Does not currently support wireless display. As of writing, it uses a WDDM 1.2 driver, versioned 9.17.13.879. Perhaps with a bit of luck Microsoft/NVIDIA will issue out an update.
Samsung ATIV Smart PC Pro: Working. [David A.]
PCs with Intel HD Graphics 3000 or lower: No WDDM 1.3 drivers at this time.
PCs with Intel HD Graphics 4000, Iris Pro (5200), or P4### variants: Working. (Inbox drivers.)
PCs with NVIDIA graphics supported by current Windows 8.1 preview drivers: Not working, appears to be a lack of driver-level Miracast support.