Use Wifi Direct to create a direct link between the source and screen, removing the need for a local wired or wifi network.

Your Chromecast is for streaming data across a network. This adapter is more like a wireless HDMI connection.

Both have their pros and cons.

My wireless Xbox one controller adapter didn't work with Windows 10

It does work with Windows 10, it was likely either your wireless adapter or graphics card that weren't compatible. Took me a while to get it working with my PC. In the end I had to enable the integrated Intel graphics to work alongside my AMD R270x so that the Intel integrated graphics could handle the wireless display (R270x didn't support it).

Tried on Dell XPS with 4K - no issues at all, but like i said it lags on 4K vid on youtube as example. For all office work - perfect tool!

​if you want gaming consider a Steam Link or a Nvidea Shield TV.

Wifi is direct from device to this adapter, no need for a router but there's still a tiny lag when I used it.

There is some lag, I can notice the sync is slightly off with video sometimes (sound before video) but it's not too bad for occasional use and I mainly use it for work.
It doesn't use your wifi connection, it creates it's own Wifi network between your device and itself (Wifi direct) so you can use it in hotels etc. without wifi connection.
Note that your PC must support Miracast or this isn't going to work. But this means you can stream from android/other devices that support Miracast, not just Windows.
I'm having some issues with mine though, worked fine on my Surface Pro 3 but since upgrading to the Surface Pro 4 I haven't been able to get it to connect.

I tested one briefly with a Dell Venue Pro: it was set up point-to-point between the tablet and the display adapter (i.e. not via your home network). The dongle is capable of 802.11n - so as long as your laptop/tablet has 802.11n or 802.11ac it should have sufficient bandwidth (It should work with older 802.11a/b/g, but no idea how well it would work at the slower speeds).
It worked brilliantly: virtually no lag (only noticeable if I held the tablet right beside the TV for comparison, but in practical terms: no noticeable lag at all).

Though, from the reviews everywhere there are a lot of people who were not so fortunate. I wonder: what laptop/tablet are people using that did have problems? what spec. CPU (are they Atom?)

The whole point is it doesn't use your wifi connection

I think it only works with devices with Intel Graphics support.

http://www.intel.com/content/www/us/en/support/graphics-drivers.html

Interesting to see peoples experiences with this.
I have a chromecast and FireTV stick (still in the box!) - so I thought a 3rd device would be overkill, although I do want to try this out at some point.

I have a Surface Pro and found that you can stream videos to a chromecast using an a chrome plugin called Videostream Link Here

Video compatibility may be a bit hit and miss (with high res files) but it worked well with a 720p MKV file. No sync issues and you could choose the output format (720p, 480p etc..)

For those saying video streaming does not work well, they it may be that your Windows device is not a good enough spec to handle the video mirroring.
Also it will probably be pointless trying to play a game via this method - just plug in cable if you want lag free gaming!

Anyone picking this up see fishmaster's link about 5mins in. Guy tries video and looks like it updates on the tv every.2 sec!

Was considering this for video from Stream 7. Not now till I see updated FW version.

I couldn't even stream a 480p video without stuttering in the video.. everything else was flawless, just video would not play nice.

Probably, or you could just open Kodi on the TV from your laptop as the TV will show as a second display on your laptop once the wireless adapter is setup.

Probably better running a small device with Sky Go. These Miracast things aren't suitable

1 year old?

The Intel WiDi's no good without a receiver.
This is a receiver.