So even though I ordered a Chromecast on Google Play, I went to Best Buy to get one in my hands today. (I'll be refusing the UPS delivery of the other to get my refund on that).
I can confirm that Hulu will play on Chromecast, but is so laggy that it wouldn't be a useful solution at all (the cast option for Chrome must render the video and audio on the computer and send it to the Chromecast, meaning the audio and video do not sync when it plays back from the TV). The video is so choppy it moves as a series of still images while the audio plays smoothly. It seems it would be possible for Hulu to optimize this, however, since it seems Netflix does the same thing (though Netflix plays loud and clear in high quality despite needing a constant connection with the computer to do so).
I will say that YouTube and Netflix work very well on the TV. Everything is loud and clear, and well synced up. It does take a few seconds to get the video there, but nothing too extreme.