Hi people,
Are you suggesting to get a ezcast dongle or chromecast ? (considering the recent news about chromecast)
Really depends on how and where you want to use it. For home use, either one probably be OK. I don't think you can mirror with Chromecast (not sure about Miracast). Also, I've heard that results sometimes vary; some people have complained about audio delays with Miracast.
If you want to use your Android device to watch video somewhere other than at home (say, at a motel), Chromecast will probably not work because of the types of networks available at hotels. Miracast might work, but you would not be able to connect to the hotel's wi-fi network while using it.
Personally, I have a Xbox setup for streaming video at home that works great, so I mainly use my Android stuff while in hotels. For me, the best bet is a Slimport adapter. This will give you high quality video and will let you stream from a hotel wi-fi network or using 4G. Anything that you watch on your phone, you can watch using a Slimport adapter.