I've been having a play with a Roku HDMI streaming stick, this also has miracast capability (listed as beta). Providing the wifi signal on the Linx and Roku are strong, video playback seems to be fairly stable although it does lag slightly. It works better than the much cheaper Measy device I have.
NowTV and Netflix have DRM that prevent streaming from the Linx to Miracast, you'll get a warning message to that effect if you try. A weak wifi signal or heavy bandwith use on the network seems to create juddering on video playback.