I have a 1st gen iPad 32GB + WiFi and AppleTV 2nd gen.
I'm having issues playing back streaming content from my iPad to my AppleTV over AirPlay. An example of this is audio from Pandora (Internet), and another is playing back films from Movies (local). When streamed to my iPad and then to AppleTV via AirPlay, it is "choppy" by the time it gets to the AppleTV.
When attempting the same thing from my iPhone 4S, I have no issues.