Screen mirroring is now fully supported in Android 4.3. The recent update enables Miracast on the Nexus range of devices.
One of the main reasons schools have chosen iPad over Android is the iPad's brilliant AirPlay screen mirroring. The technology allows a teacher to stream a live view of their iPad's screen to a TV or projector and is a hugely effective teaching tool, but until now this feature had been missing from Android.
The recent 4.3 update for Android enables Miracast support for the Nexus 4, Nexus 10, and Nexus 7 (2013). Any device with both WiFi Direct support and Android 4.3 should also be able to use Miracast to screen share.
The benefit of Miracast is that it is an industry standard with the potential to be built into any device. Windows 8.1 will also support Miracast technology as standard. Apple's solution requires you to own an iPad and an Apple TV. With Miracast you could purchase any tablet — potentially even an iPad, were Apple to support it — and have it stream wirelessly to your TV.
The following is from the Google Support pages where Google specifically states “Some or all of this information applies only to devices running Android 4.3.”
Nexus 4, Nexus 7 (2013) and Nexus 10 are compatible with devices that support the Wi-Fi Certified Miracast™ protocol for wireless display. You can mirror the screen and wirelessly stream video and audio to a variety of displays and other devices that support Miracast, even when a standard Wi-Fi network isn’t available. For example, you can use wireless display to show your device’s screen on a TV equipped with a certified Miracast adapter.
For more information, see the documentation that comes with the Miracast-certified device that you wish to use with your tablet or phone.
How Can I Use Miracast in my Classroom?
The only thing you need is a Miracast dongle, or a set top box which supports Miracast. These can be purchased fairly cheaply from most online retailers.
Are you using a Miracast receiver in your school, let us know which one in the comments.