Be just a bit aware of what Chromecast can and cant do, and dont listen to the tv ads, they are a bit misleading. That said I have 2 chromecasts and they are a useful and well priced device.
What it can do, and does rather well is cast from Netflix, Hulu, HBOgo, Pandora, and Google Play. I dont have any google play movies yet, but it casts my 5000+ library of my music uploaded to my google play music cloud, beautifully.
What it does NOT do, at least not from an android device , for now, is cast from a web browser, even from Chrome, it does not cast your own pictures or your own videos. It can cast from a Windows based PC, but not Android, how does THAT make any sense, but such is life.
Also, the set up can be tricky. I have set up 2 so far, and apparantly if you try to set it up with a cell phone it gets confused between accessing the wifi, its internal chromecast network, and the data network of the phone. I know now, I have to set it up initially with either an android wifi only tablet. , or a PC. But once its set up, its easy and cool to control from a cell phone.
I think its a very new device, and not fully matured yet, but knowing its put out by google, Im betting it will take off like a rocket, and have more and more apps as time goes by. HBOgo is new to it, and works great!