As of earlier today and nonstop throughout, we've started to see the tomatometer on Rotten Tomates update. It has bounced all over the place as different reviewers chime in with their two cents. I'm noticing a pretty heavy trend of people that like pony enjoying it, while those that went in blind tend to rate it a bit lower. Chances are this will take a while to stabilize, especially since the vast majority haven't seen it yet. Expect that number to change a bunch.
You can follow along over here.
