There are cheaper alternatives
Google’s Chromecast - $32
Amazon’s Fire TV Stick -$39.
Both these devices can mirror your phone or tablet.
Amazon had a promotion recently where you can preorder Fire TV Stick for $19.
@ Architect - ordered mine for $20 and can’t wait to try out.
@ Gus - I have Cromecast, but couldn’t resist the promo and ordered Fire stick too. Would make a nice present.
@ Architect - I have chromecast, Sony Google TV, fire tv and bore the sick 
ie great potential in these devices, not just for Netflix … Still not sure how though.
@ Architect - I ordered two Fire TV sticks, because at $19 each, if Miracast works, they’d be the cheapest screencasting solution by far. If the Miracast support is poor, I’ll probably return them and try the MS receiver.
I have a Chrome Cast, but you cannot mirror the browser or screen on all devices. Just the ones in beta. Works great for YouTube and Netflix though. Disappointed about the browser. 3rd party apps attempt to mirror the browser, but the audio is choppy when doing so.
What’s a TV?
@ willgeorge - I just got this thing yesterday and really like it so far. I had previously purchased a Belkin Miracast dongle, which had a lot of issues (overheated, pixilation). But the Belkin had some HDMI-CEC integration that I really liked. So far, this Microsoft one is super easy to connect to and video quality is fantastic. It really needs CEC control though. All the HDMI dongles need good CEC implementations. When a device connects, the dongle should send a CEC message to the CEC bus to change inputs. That way, I can pull out my phone and open a video and not have to touch the remote control. Then when I deactivate my phone’s connection, the dongle should send the source disconnected command and/or restore to the previously set source. Ideally, it would send the Pause command before and the resume playback command as well. That way, if I am watching TV and when to show my wife and e-mail, text, or something on my phone, I can do it, and resume what I was doing.
I have strong opinions in this area. I wrote a Windows application a while back to control CEC from a PC. HDMI-CEC is way under-utilized.
Update: It doesn’t work with my wife’s Lumia 1020, or our Surface RT, but it does work with my Lumia 1520 and VivoTab8 tablet. So, it’s hit and miss on compatibility.
I ordered one at $19 but if I’d seen anything on the sales page about it supporting Miracast and being able to cast my laptop screen to it then I would have definitely ordered another one just to keep in my bag. I still see no mention of Miracast on the Amazon page. Did you see somewhere that you should be able to cast from Windows to the Fire Stick?
@ ianlee74 - It was in the press release, and one of my former co-workers who is now at Amazon confirmed it with some of his internal sources.
I hope it works well. To me the ability for Apple products to cast to Apple TV is a huge advantage to going with that family of devices.
Me, too. Did not have great luck with the other Miracast receiver I tried, but at 1/3rd the price, I figured this was worth a try.
From experience, I can tell you that presenting from a tablet via Miracast, when it works, is a very cool experience. You can walk around stage while not only flipping slides, but annotating them etc.
It’s a different style of presenting.
Pete