With the release of the Windows 8.1 GA rollup (KB2883200), Microsoft seems to have inadvertently broken wireless display (Miracast) support on the Surface Pro.
Affected users will have trouble discovering Miracast capable devices, such as the NETGEAR Push2TV and ActionTec ScreenBeam.
Fix: New Marvell AVASTAR drivers (14.69.24044.150) are available in, funny enough, the Surface Pro 2 driver and firmware pack. They apply to the Surface Pro as well. I'm told these will eventually be pushed out via WU as well. [added 10/25/2013]
It's not clear where the fault lies, but I suspect we'll be seeing updated wireless drivers (Marvell AVASTAR 350N) in the very near future.
For more information on Miracast support in Windows 8.1, check out my previous article.