So I got a Chromecast for Xmas and it seems basically worthless. I have my PS3 for netflix etc. If I want to stream movies from my PC, I put them on my homegroup and stream them from my PS3. I can do the same for family videos, pictures, music, etc stored on my PC. The only thing I did try that my PS3 couldn't do, was stream a flash video from my PC in the chrome browser, to my TV, but it was laggy and out of sync with audio/video. It was just easier to download it, and drop it in my homegroup and play it on my PS3.
Google really needs to open up dev support for this thing. Now if we would get streaming on something like MX player, or one of the other video apps, for me it would take this thing from useless to pretty much invaluable.