I recently bought a 25$ worth miracast dongle from EBAY like this one,
And I thought to share my experience after playing with it for a few days.
First, when you purchase, make sure you by a dongle with at least 256mb of ram since it uses it like a graphic card on your pc.
The package includes: the dongle, charging cable, hdmi extension cable, and a very tiny user manual in English.
About the HDMI extension cable: for esthetics reason I chose to stick the dongle directly to the HDMI input in the back of my Samsung TV. However, it seems that the reception is weaker that way and I experienced some freezes, until I used the extension cable and allowed an "eye contact" between my lg g2 and the dongle.
Setup: the setup is extremely simple- one cable to HDMI input, one cable to USB input (just for power). When you turn on your TV and choose the appropriate hdmi channel you will see a status screen. There is a micro switch on the dongle surface that allows you to toggle between modes (dlna, miracast and airplay) make sure you choose the miracast mode.
My device is D802 running stock 4.2.2. I just turned on the miracast switch on the quick settings menu and choose the device. A few seconds for pairing and the magic begins…
There is a standard delay between 0.5 to 1 second. Orientation change responds very quickly and flawlessly. I was surprised that all audio and sound effects are also mirrored. Standard apps work very nice within the limit of the delay: mail, messaging, Calendar , calculator, contacts etc.
Rich media apps: gallery, maps, camera, image editing. Usually works well . Sometimes when doing fast transitions or zooming, the image gets pixilated until it stables.
Internet browser and browsing based apps: works extremely nice except when scrolling very fast, then sometimes the pixilation issue appears for a second.
Video content on the internet (incl. youtube): here is the worst issue. Since, most of the wifi bandwidth is dedicated to the wifi-direct for miracast, there is very little left for internet browsing, so watching stream video especially if in HD quality is almost impossible.
Video playback: there is some difference between lg stock video player and others (I've used mobo player). The stock player is integrated with miracast and blacks out the device screen while playing video. Playing video with this player works remarkably well even in full HD. Quiet rarely some frame dropping will occur. Mobo players performance shows more frame dropping and video will also run on yours device screen.
Gaming: it seems that miracast mirroring does not consume to match processing power (at least not from our G2 beast) and most of casual games run uninterrupted. However, due to the delay I've mentioned it is almost impossible to play the on the tv, just mirror it maybe for someone else to watch.
This cheap tiny thing can easily sit in your pocket/purse/bag and can be used as am "emergency media streamer" on the road, at work, friends and even at home,