I ordered my Chromecast from the Google Play store the morning after it was announced. It was immediately backordered and took about 3 weeks to arrive. But it's hear and I love it.
This is a fairly small device and hides very easily behind the TV.
The HDMI port on my TV cannot power the Chromecast on it's own. For others with this problem the Chromecast comes with a 5ft. USB cord and an AC adapter. This TV has a USB port close to the HDMI ports, so I didn't have a need for the AC adapter.
It took me 30 seconds to plugin the HDMI dongle and USB cord. It then took about 3 minutes to follow the directions in step 3 below. This step had me download a program to my Mac. Once the program opened, it found the Chromecast, asked me to input the wifi network passkey, and completed the setup. (It was seriously too easy.)
What it can do...
Mirror any Chrome tab on a Mac onto the TV.
Instantly stream YouTube or Netflix in HD from: iPad, iPhone, Android, Mac,
Allow mobile devices to multi-task while streaming. I was able to check email, surf the web, and use other apps while streaming.
Automatically switch the TV input to Chromecast when I begin casting. In other words if the TV was on Cable, Dish, or BluRay, and I decide to cast a video from Netflix, the TV will automatically switch the input and save me the hassle of finding the remote to switch the input manually. (This feature is only supported if your TV’s HDMI ports support auto switching.)
Play audio and video files inside a Chrome tab on a Mac or PC. I was able to drag music file and a video file into Chrome from my local hard drive and play them on the TV.
Stream Google Play Music. However, only music from the cloud.
Control volume while listening to music (although somewhat limited).
Control the Chromecast with multiple devices at once. My wife and I sat down for nearly 2 hours playing our favorite YouTube videos. She had an iPhone and I used a Nexus 7. When she had selected a video to cast, the YouTube app on my Nexus showed the video that was currently casting. I was able to search for another video and either play that video instantly or add it to the queue. It was simple to understand and use.
The Chromecast allows the user(s) in the room to create a play queue with the YouTube app. Videos then continue to play from one video to the next until the app runs out of videos in the queue.
What it can’t do...
Mirror a Chrome tab on iPad, iPhone, or Android. I assume that this is due primarily to the fact that Chrome on mobile devices doesn’t allow extensions.
Stream Pandora from a mobile device. Google and Pandora have announced that this is a feature they are currently working on.
Play Music from local memory. My Android phone has music in the cloud and on the SD card. While using the Google Music app I was able to play music from the cloud but not from the SD card. Since Google Music puts all the songs together regardless of their location, this was a terrible experience.
*Note - I did not have a PC to test most of these features with.
So is the Chromecast worth the $39 price tag? Absolutely! With the TV I'm using, I had been streaming Netflix on the Wii and couldn't stand the awful resolution. With the Chromecast, everything was in HD and it looked great! I don't think I have watched as much YouTube in one day as I have with Chromecast. I love being able to browse Netflix on my tablet instead of the Wii. I already have my iPad, phone or laptop next to my while I'm watching TV anyway. Now those devices are more useful while watching TV.
Is this a good device for the classroom? It depends on what you want to do and who you want to do it. If you want your students to have the ability to share their screen with the class on the projector, then yes. This is very inexpensive device and has lots of power to engage students.