I just recently got myself a Chromecast to use specifically with Netflix and Hulu Plus (casting from an iOS device).
Thanks to this forum I knew how to proceed for everything beforehand, using Smart DNS in my router, blacklisting google's DNS servers, etc. I have a TP-Link router.
Netflix is working perfectly, bumps to the 720p stream in about 6 seconds and another 5-6 seconds later it streams at 1080p without any noticeable drops so far.
Hulu Plus however is being problematic. It might smart in HD (sometimes) but either a few minutes later or after the commercials it drops to SD quality and rarely ramps up again. Starting the stream again helps, but only for a short while.
As I currently don't have another H+ device to test, i was wondering if the hulu plus implementation with Chromecast is indeed flawed or if this is happening just to myself (I understand that being overseas might not help - although I'm not sure which CDN I'm getting the content from), but it's really annoying seeing all the godawful pixels on my screen constantly - the Ads... pfft, well, those are always in 720p, go figure!
Anyway, hopefully you'll be able to share your experiences with me!