Watched on AppleTV using the Yahoo app. It was great. Picture was great, etc. Paused it when I needed to get more coffee, and picked it up just fine. Of course, I'm lucky here in Rochester to have Greenlight and not that POS company Time Warner, so my internet connection is 500mbps and never a buffering problem. I have my appleTV wired with cat5 to my router.
I expect anyone who had any buffering was a victim of either the slowness of their own home wireless network, or the slow speed of their internet service.